Each Sept. 1, active Major League rosters can expand from 25 to 40 players, and with that expansion come reinforcements for teams in the postseason hunt, as well as a glimpse of the future for other clubs looking toward next season.
Here's a look at every Top 30 prospect from around baseball that was called up with rosters expanding Saturday:
Astros
4. Cionel Perez, LHP
6. Josh James, RHP
Perez, a 22-year-old left-hander out of Cuba, made his MLB debut for Houston on July 11 vs. Oakland, giving up a run on two hits, walking two and striking out two over 1 2/3 relief innings. In 20 appearances (11 starts) between Double-A Corpus Christi and Triple-A Fresno this season, he posted a 2.08 ERA with a 29 percent strikeout rate.
James, a hard-throwing right-hander, made his big league debut for the Astros on Saturday, giving up three runs on three hits against the Angels, walking three and striking out nine over five innings. He hit 101.1 mph with his fastball, tying Shohei Ohtani for the fastest pitch thrown by a starting pitcher this season, according to Statcast™. More » 
Blue Jays
5. Anthony Alford, OF
10. Sean Reid-Foley, RHP
19. David Paulino, RHP
20. Reese McGuire, C
21. Jonathan Davis, OF
22. Richard Urena, SS/2B
29. Rowdy Tellez, 1B
Alford was in the bigs for six games in May after making his Major League debut in 2017. The No. 89 overall prospect is a 70-grade runner who swiped 17 bags in 105 games with Triple-A Buffalo this year, but he only managed a .240/.312/.344 slash line.
Reid-Foley made his first two Major League starts in August, giving up nine earned runs in 9 1/3 innings against the Royals and Yankees. In 24 starts between Double-A New Hampshire and Triple-A Buffalo this season, he posted a 3.26 ERA. More »
Paulino, who has pitched since July 17, was acquired from the Astros in the Roberto Osuna deal on July 30. The 6-foot-7 righty has posted a 4.67 ERA in seven starts this year, including three rehab outings in the Gulf Coast League.
McGuire was acquired from the Pirates in the Drew Hutchinson deal in 2016. The 2013 first-round Draft pick hit .233 in 96 games with Triple-A Buffalo this season.
Davis, a 15th-round pick in 2013, hit .282 with 10 homers across two levels this season. The 5-foot-8 outfielder has plus speed with a 60-grade run tool.
Urena has seen time in the bigs this season already, batting .273 across two MLB stints in 2018. The 22-year-old hit .209 across two levels in the Minors this year.
Tellez spent the 2018 season with Triple-A Buffalo, batting .270 with 13 homers in 112 games. It's the first big league callup for the 6-foot-4, 220-pound first baseman.
Braves
2. Kyle Wright, RHP
7. Touki Toussaint, RHP
13. Bryse Wilson, RHP
The Braves added three top prospects to their bullpen for the stretch run in Wright, Toussaint and Wilson. Wright, the No. 24 prospect overall per MLB Pipeline, and the fifth overall selection in the 2017 MLB Draft, has impressed at every professional level he's pitched in to this point, posting a 3.37 ERA in 36 appearances (33 starts) between the Rookie level in 2017 to Triple-A Gwinnett this season.
Toussaint, No. 74 overall, was the 16th overall selection by the D-backs back in 2014 before being traded to Atlanta the following year in the Bronson Arroyo deal. Though it took longer than hoped for him to develop in the Braves' system, he's had a strong 2018 campaign, posting a 2.38 ERA in 24 appearances between Double-A Mississippi and Triple-A Gwinnett and earning a spot in the Futures Game. Toussaint made his Major League debut on Aug. 13, starting and going six innings against the Marlins, yielding a run on two hits, walking two and striking out four.
Wilson made his big league debut a week after Toussaint, tossing five scoreless innings in a start against the Pirates at PNC Park on Aug. 20. The 20-year-old right-hander has moved quickly through Atlanta's system, pitching at three different levels in 2018. Between Class A Advanced Florida, Double-A Mississippi and Triple-A Gwinnett, he turned in a 3.44 ERA in 25 appearances (23 starts). More » 
Brewers
9. Jacob Nottingham, C/1B
Nottingham, a 23-year-old catcher/first baseman, hit .281/.347/.528 with 10 home runs in 50 games for Triple-A Colorado Springs. He also appeared in seven games for Milwaukee earlier this season, going 4-for-20 with a double. More »
Cardinals
15. Edmundo Sosa, SS/3B
22. Giovanny Gallegos, RHP
29. Daniel Poncedeleon, RHP
Sosa, who signed with the Cards in 2012 out of Panama, slashed .270/.313/.420 with 12 homers in 123 games between Double-A Springfield and Triple-A Memphis in 2018. His best tool is his 60-grade defense, but he's also a career .281 hitter in the Minors.
Signed out of Mexico by the Yankees in 2011, Gallegos was sent to St. Louis in July in the deal for Luke Voit. He posted a 0.54 ERA in 13 relief appearances for Memphis, helping the Redbirds win the Pacific Coast League title and the Triple-A National Championship.
Poncedeleon held Cincinnati hitless for seven innings in his big league debut July 23. In 19 appearances (18 starts) at Triple-A Memphis, he posted a 2.24 ERA. More »
Cubs
23. James Norwood, RHP
Norwood is a hard-throwing right-hander who struggled early in his professional career as a starter, but he has seen more success out of the bullpen. In five starts for the Cubs earlier this season, he had a 4.76 ERA (three earned runs in 5 2/3 innings). In 40 appearances between Double-A Tennessee and Triple-A Iowa, he posted a 2.50 ERA, striking out 57 of the 210 batters he faced. More »
D-backs
13. Jimmie Sherfy, RHP
18. Yoan Lopez, RHP
Sherfy gets another chance to help the D-backs in a pennant race. In the 15 Major League appearances he has made over the past two seasons, he's been excellent, to the tune of a 0.61 ERA over 14 2/3 innings. He was hit hard by the Dodgers in two appearances during last October's National League Division Series, surrendering four runs over an inning-plus in Games 1 and 2. In 38 games for Triple-A Reno, he posted a 1.60 ERA while fanning 58 of the 187 batters he faced. More »

The D-Backs called up Lopez from Double-A Jackson, where he finished this season with a 2.92 ERA, a 1.04 WHIP and 87 strikeouts in 61 2/3 innings. In 45 games, he was 12-for-17 in save opportunities. More »
Dodgers

1. Alex Verdugo, OF
   Verdugo, the No. 28 prospect overall, is "Major League-ready," as Dodgers manager Dave Roberts said upon his callup, and he could get an opportunity to show that as Los Angeles seeks its sixth consecutive NL West title. The 22-year-old outfielder has had two stints with the big league team this season, slashing .280/.345/.440 with a homer in 15 games. He hit .329/.391/.472 with 10 homers and eight steals for Triple-A Oklahoma City en route to being named a Pacific Coast League Midseason All-Star and Postseason All-Star. More » 
   Giants
   
2. Ray Black, RHP
   
3. Abiatal Avelino, SS/2B
   Black has a great fastball but hasn't been able to really show it consistently due to a lengthy injury history. He had a strong Triple-A campaign for Sacramento this season, however, posting a 2.52 ERA in 36 games this season, striking out 66 of 136 batters (49 percent). In 16 Major League appearances, he has allowed 10 runs in 15 2/3 innings (5.74 ERA). More »
   Avelino, who was acquired from the Yankees in the Andrew McCutchen deal, went 2-for-13 in his first three games in the Giants' organization. Before he was traded, Avelino hit .252 with Triple-A Scranton Wilkes/Barre and .337 with Double-A Trenton.
   Indians
   
4. Eric Haase, C
   Haase hit .236/.288/.443 with 20 homers in 120 games for Triple-A Columbus this season. Saturday's promotion is the 25-year-old catcher's first big league callup. More »
   Mariners
   
5. Matthew Festa, RHP
   
6. Nick Rumbelow, RHP
   Festa, 25, made his big league debut with Seattle on July 13 and logged two innings out of the bullpen on Aug. 19 in his only other appearance so far this season. The right-hander spent much of his year at Double-A Arkansas, where he totaled 20 saves in 22 chances while averaging 12.3 strikeouts-per-nine. More »
   Acquired from the Yankees in November 2017, Rumbelow missed the first two months this season due to neck and back issues and then bounced between Triple-A Tacoma and the big leagues once healthy. The 27-year-old right-hander owns a 6.75 ERA over 13 1/3 innings (nine games) with the Mariners compared to a 1.83 ERA and 11.9 K/9 over 19 2/3 frames (15 games) in Triple-A.
   Marlins
   
7. Sandy Alcantara, RHP
   
8. Jeff Brigham, RHP
   Brigham, a 26-year-old right-hander, posted a 2.49 ERA n 16 starts between Double-A Jacksonville (seven) and Triple-A New Orleans (nine).
   Alcantara, a 22-year-old right-hander, made his big league debut for the Cardinals in 2017 before being traded to Miami in the Marcell Ozuna deal last offseason. In 22 starts between Class A Advanced Jupiter and Triple-A New Orleans this season, he posted a 3.90 ERA. More »
   Mets
   
9. Eric Hanhold, RHP
   Hanhold came to the Mets organization last summer in the trade that sent Neil Walker to Milwaukee. He posted a 4.20 ERA with more than a strikeout per inning over four levels this season, missing much of June and July due to an oblique injury. More »
   Nats
   
10. Victor Robles, OF
    
11. Erick Fedde, RHP
    Robles, the No. 5 prospect in baseball, is one of the most well-rounded prospects in the game, sporting a 55 grade or better for all five tools on the scouting scale. Robles, who was sidelined with a left elbow injury earlier in the season, batted .278 with Triple-A Syracuse this season. He's 6-for-24 in his big league career.
    Fedde, a 2014 first-rounder, is returning from injury after being sent to Syracuse on a rehab assignment. The righty had a 4.29 ERA across two levels this season, with 13 of his 14 starts coming with the Chiefs.
    Orioles
    
12. Luis Ortiz, RHP
    
13. Cody Carroll, RHP
    
14. D.J. Stewart, OF
    Ortiz went 2-1 with a 3.66 ERA in six starts for Triple-A Norfolk after he was acquired from the Brewers at the Trade Deadline. The 22-year-old has a mid- to upper-90s fastball and a slider that grades out as plus as well. He's also developed an average changeup and uses a curveball sparingly.
    Carroll was dealt to Baltimore by the Yankees along with Dillon Tate and Josh Rodgers in the trade for Zach Britton in July. Carroll allowed three earned runs in 4 2/3 innings with Norfolk following the deal after posting a 2.38 ERA in 41 2/3 innings with Triple-A Scranton Wilkes/Barres this season.
    Stewart, a first-round pick in 2015, hit .235 in his first taste of Triple-A this season. The 6-foot, 230-pound outfielder stole 11 bases this season and has 61 steals in his Minor League career.
    Padres
    
15. Francisco Mejia, C/OF
    Mejia was called up from Triple-A El Paso, where he slashed .328/.364/.582 with seven homers and 23 RBIs in 31 games after being acquired from the Indians in the Brad Hand deal in July. MLB's No. 21 overall prospect was particularly hot down the stretch, hitting .359 with four homers in his final nine games of the Minor League season. 
    Phillies
    
16. Enyel De Los Santos, RHP
    
17. Dylan Cozens, OF
    20 Drew Anderson, RHP
    Prior to his September callup, De Los Santos had already appreaed in three games with the Phillies this season. The right-hander went 1-0, including two starts, and posted an ERA of 6.00. De Los Santos spent most of the season at Triple-A, where he went 10-5 with a 2.63 ERA over 22 starts.
    Cozens went 2-for-20 in his first extended Major League stint earlier this year, but he provides a combination of speed and power in a reserve role. In 88 games for Triple-A Lehigh Valley, he slashed .246/.345/.529 with 21 homers and nine steals. More »
    Anderson made one start and pitched in two Major League games earlier this season, but like De Los Santos, spent the bulk of the season with Lehigh Valley. Anderson, 24, has an impressive fastball-curveball combination and has made strides with his changeup as well.
    Pirates
    
18. Kevin Kramer, 2B/SS
    
19. Clay Holmes, RHP
    Kramer, a second-round pick out of UCLA in 2015, had an impressive season with Triple-A Indianapolis in 2018, batting .311 in 129 games and stealing 15 bases.
    Holmes made his big league debut earlier in 2018, and he allowed 16 earned runs in 17 2/3 innings pitched. Holmes was much more successful with Triple-A Indianapolis this season, posting a 3.40 ERA in 22 appearances.
    Rangers
    
20. Willie Calhoun, OF
    
21. C.D. Pelham, RHP
    
22.  Yohander Mendez, LHP
    It's the second callup of the season for Calhoun, who hit .275 in 22 games in the big leagues earlier this year. Calhoun's bat is his strong suit, with 60-grade hit and power tools. He hit .294 and homered nine times in 108 games with Triple-A Round Rock this year.
    Pelham, a lefty reliever, was dominant in 23 games with Class A Advanced Down East, posting a 1.95 ERA and notching 11 saves. He struggled after his promotion to Double-A Frisco, though, allowing 13 earned runs in 19 innings. 
    Mendez made a pair of appearances in June. His lone start didn't go well, and he was demoted for violating team rules. However, he's back for the season's final month and perhaps he's learned from his earlier experience. More »
    Rays
    
23. Nick Ciuffo, C
    Ciuffo, the Rays' defensive player of the year in 2016 and '17, was called up from Triple-A Durham, where the 23-year-old hit .262 with five homers, 28 RBIs and a .681 OPS in 60 games with Durham.
    Red Sox
    
24. Bobby Poyner, LHP
    Poyner made the big league club out of Spring Training this year before returning to the Minors after straining his left hamstring. The 25-year-old southpaw had a 3.14 ERA in 33 games for Triple-A Pawtucket.
    More »
    Rockies
    
25. Garrett Hampson, INF
    
26. Sam Howard, LHP
    Hampson already has a bit of Major League experience under his belt as this will be his third stint in the Majors. The 23-year-old spent the bulk of the season in the Minors and hit .311 in 110 games with Double-A Hartford and Triple-A Albuquerque. Hampson has played both second and shortstop this season and even got a few reps in the outfield.
    Howard also has had a brief taste of the Majors, making his debut on June 10. The lefty throws a lot of strikes, but doesn't have a true dominant pitch so he'll have to rely on command moreso than stuff.
    Tigers
    
27. Christin Stewart, OF
    
28. Matt Hall, LHP
    
29. Sandy Baez, RHP
    Stewart, who hit 25 homers over 125 games this season, will be making his first trip to the Major Leagues. The 24-year-old has plenty of power, but strikeouts were a concern when he was drafted. However, he was able to cut those down this season, while continuing to hit for power. Defensively, Stewart isn't an elite defender, but has a strong work ethic and has continuously made strides in that area. More »
    Hall put together a solid season, going 9-2 with a 2.13 ERA across two levels. The left-hander made 14 starts and also got some work out of the bullpen as he made 23 relief outings. Hall was promoted to Triple-A in July and went 4-0 with a 2.67 ERA over 10 starts. Hall's fastball barely reaches 90 mph, but he has perhaps the best curveball in the Tigers' system, which helps play up his heater. More »
    Baez is back for his second stint with the Tigers after posting a 5.64 ERA in 33 appearances (15 starts) with Double-A Erie. The 24-year-old right-hander went with 4 1/3 scoreless innings against the Yankees on June 4 in his big league debut. More »
    Twins
    
30. John Curtiss, RHP
    
31. Zack Littell, RHP
    At Triple-A Rochester, Curtiss posted a 2.77 ERA with 61 strikeouts in 55 1/3 innings this year. He logged a 2.77 ERA, converting on 10 out of 12 save opportunities for Rochester. More »
    
    Littell made his big league debut with the Twins in June and then made another appearance in July. The 6-foot-4 right-hander had a 3.98 ERA and 1.36 WHIP in 24 games (20 starts) between Double-A Chattanooga and Triple-A Rochester this season, striking out just over a batter per inning (130 in 129 IP).
    White Sox
    
32. Jose Ruiz, RHP
    Ruiz, a converted catcher originally signed by the Padres in 2011, was impressive out of the bullpen this season for Class A Advanced Winston-Salem and Double-A Birmingham. Ruiz sported a 3.07 ERA across both levels this season and has notched 16 saves while holding batters to a .188 average.
    Yankees
    
33. Justus Sheffield, LHP
    
34. Jonathan Loaisiga, RHP
    
35. Chance Adams, RHP
    Sheffield, a 2014 first-round Draft pick, was acquired by the Yankees from the Indians in the package for Andrew Miller in '16. The 22-year-old south paw, who is No. 27 on the Top 100, sported a 2.48 ERA across Double-A Trenton and Triple-A Scranton/Wilkes-Barre this year. He was shifted to a relief role in August with the hopes of helping the big league club's bullpen. Sheffield logged a 2.91 ERA in seven bullpen appearances (four of them for multiple innings) down the stretch and during the postseason for the RailRiders.
    Loaisiga, the No. 73 prospect overall, returns to the Yankees after beginning the season in Class A Advanced Tampa. He was called up from Double-A Trenton in June and went 2-0 with a 3.00 ERA in four big league starts. Over three levels, the 23-year-old went a combined 6-1 with a 2.89 ERA over 14 starts this season.
    Adams, 24, appeared his first two big league games back in August, tossing five innings of three-run ball as a starter in his debut before coming out of the bullpen later in the month. He's continued to work in relief back at Triple-A Scranton/Wilkes-Barre, where Adams allowed one run over 6 1/3 innings in four appearances en route to a September callup.