30 potential callups to get excited about

Whether your team is competing for a postseason spot or looking ahead to the future, Saturday, Sept. 1, is a date that has to be circled on the calendar.
Starting on the first day of the month, all 30 teams can expand their rosters at the big league level, adding as many players from their 40-man roster as they wish. For teams out of the race, it can be a great opportunity to give someone an extended audition and first taste of the big leagues. For teams hoping to play into October, roster expansion can provide an extra boost for that playoff push.
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The MLB Pipeline staff has weighed all of the variables that come into play with these roster decisions -- Is the player already on the 40-man roster? Is there an opportunity for him to play or fill a role with the Major League club? Is his Minor League team in a playoff race? Is a pitcher nearing an innings limit? -- in choosing one player per organization to get excited about potentially seeing come September.
These players are by no means guaranteed to be called up, but we should see many of them during the final month of the season.
American League East
Blue Jays
Anthony Alford, OF, Blue Jays' No. 5/No. 91 overall
Nothing would make baseball fans happier than a September promotion for Vladimir Guerrero Jr. Unfortunately, all signs point to a likely 2019 arrival for the 19-year-old phenom. The Blue Jays still have plenty of interesting prospects deserving of a callup, including outfielder Anthony Alford, who has struggled this season in Triple-A but also possesses all-around tools that are among the best in Toronto's system.
Orioles
DJ Stewart, OF, O's No. 23
After breaking out with a 21-homer, 20-steal campaign last year in Double-A, Stewart's production has backed up in 2018 with his move up to Triple-A. He does enough things well to profile as a bench outfielder in the Majors and could get a look in September as the club weighs whether or not to add Stewart to its 40-man roster this offseason.
Rays
Colin Poche, LHP, Rays' No. 24
Poche has been perhaps the most dominant reliever in the Minors this year, averaging more than 15.0 strikeouts-per-nine across the Double-A and Triple-A while also proving capable of working multiple innings. Both qualities make the 24-year-old left-hander a logical September callup for Tampa Bay, which continues to employ a unique strategy with their big league staff.
Red Sox
Michael Chavis, 3B/1B, Red Sox's No. 1/No. 99 overall
Chavis finished third in the Minors in extra-base hits (68) and fifth in homers (31) a year ago, and he has regained his power stroke after serving an 80-game suspension to begin 2018. He could provide righty power off the bench and complement lefty hitters Rafael Devers and Mitch Moreland.
Yankees
Justus Sheffield, LHP, Yankees' No. 1/No. 27 overall
Sheffield can show three plus pitches at times and has had little difficulty dealing with Triple-A hitters at age 21. Behind Luis Severino, he's New York's best hope for a difference-making starter in the playoffs.
AL Central
Indians
Eric Haase, C, Indians' No. 24
A member of Cleveland's 40-man roster, 25-year-old Haase seems poised for his first big league promotion after a full season in Triple-A in which he continued to hit for power while throwing out attempted basestealers at nearly a 50-percent clip.
Royals
Nicky Lopez, SS/2B, Royals' No. 7
Lopez has been the Royals' most consistent Minor League performer since they drafted him in the fifth round two years ago. He's not as flashy a defender as free-agent-to-be Alcides Escobar or as tooled up as Adalberto Mondesi, but he's a more reliable hitter than either and steady at either middle-infield spot.
Tigers
Christin Stewart, OF, Tigers' No. 6
Stewart's 21 home runs leads the organization, which should surprise no one since the outfielder did the same thing in both 2016 and '17. But he's done it while also upping his walk rate and cutting his strikeout rate. It's time to see how the power plays in Detroit.
Twins
Nick Gordon, SS/2B, Twins' No. 3/No. 73 overall
After starting off well upon reaching Triple-A, Tom's son (and Dee's brother) has struggled in the International League. Still, he's ready for an opportunity and should get a shot to play in 2019, so why not give him a shot at short or second now?
White Sox
Eloy Jiménez, OF, White Sox No. 1/No. 3 overall
When Jimenez hasn't been dealing with some minor injuries, he has destroyed upper-level pitching as a 21-year-old. The only reason not to call up him up would be to keep them from accruing service time.
AL West
Angels
Matt Thaiss, 1B, Angels' No. 5
While it would be exciting to see someone like ultra-toolsy Jo Adell in the big leagues, he's likely a year away. Thaiss has career highs in home runs, total bases and slugging right now, and though his walk rate has taken a hit, his left-handed bat could help the Angels right now.
Astros
Josh James, RHP, Astros' No. 6
While Forrest Whitley, the game's best pitching prospect, would make more headlines with a callup, James might be a more realistic option. He'll have to be added to the 40-man roster in the offseason (Whitley won't), as he's battling Kopech for the Minor League strikeout lead and his fastball/slider combination could make him a useful October bullpen piece.
Athletics
Jorge Mateo, SS/OF, A's No. 7
Mateo and his 80-grade speed could be a major weapon off the A's bench as the club battles for a spot in the postseason. The 23-year-old shortstop led the Minors with 82 steals in 2015 and tied for third with 72 a year ago.
Mariners
Matthew Festa, RHP, Mariners' No. 8
Festa made his big league debut on July 14 with a scoreless relief appearance against the Rockies. He's otherwise spent the season in the Texas League, posting strong numbers as Double-A Arkansas' closer. The 25-year-old right-hander doesn't miss a ton of bats, but he has good feel for a deep arsenal along with a strong track record against same-sided hitters.
Rangers
Willie Calhoun, OF, Rangers' No. 2/No. 48 overall
Calhoun combines power and patience better than most prospects and hit .275/.325/.391 in a four-week stint with the Rangers while filling in for an injured Nomar Mazara. Sent down last week, he's a lock to rejoin Texas in September.
NL East
Braves
Kyle Wright, RHP, Braves' No. 2/No. 24 overall
There are so many prospects to choose from here, but Wright, the Braves' top pick from the 2017 Draft, is already in Triple-A, knocking on the proverbial door. The right-hander is in the top 10 in the organization in ERA and strikeouts and showed in the Futures Game he's not afraid of coming in out of the bullpen in a tight spot if necessary.
Marlins
Sandy Alcantara, RHP, Marlins' No. 2
The hard-throwing right-hander earned the win in his Marlins debut (also his first big league start) on June 29, but subsequently landed on the disabled with a right axillary infection. Now healthy and pitching well at Triple-A New Orleans, Alcantara should receive an extended look in Miami's rotation next month as the organization looks towards 2019.
Mets
Peter Alonso, 1B, Mets' No. 2/No. 64 overall
Not only does Alonso lead the Minors in homers (32) and RBIs (109), he's also driven in as many runs as any professional hitter at any level. He's one of just five Minor Leaguers to reach the 30-homer plateau, doing it while getting on base at a .394 clip.
Nationals
Victor Robles, OF, Nats' No. 1/No. 5 overall
The enormous success of 19-year-old Juan Soto has made Robles a bit of an afterthought in the Nationals' outfield, but there's no denying that the 20-year-old Robles is still very much a special talent in his own right. Triple-A Syracuse won't make the International League playoffs, so expect Robles to see time at all three spots in Washington's outfield down the stretch.
Phillies
Ranger Suárez, LHP, Phillies' No. 8
The Phillies have relied on young players so much in their surprising season, so it might be unfair to ask more of their farm system. But Suarez, a starter long-term who did pick up a big league start earlier this year, could certainly help out in the bullpen down the stretch. Lefties in Triple-A have just a .167 batting average against him.
NL Central
Brewers
Zack Brown, RHP, Brewers' No. 9
After spending a month on the shelf with an ankle sprain, the 23-year-old is a potential bullpen option for the Brewers in September, though they'd first have to add the 2016 fifth-round pick to their 40-man roster. Brown was 9-0 with a Southern League-best 2.34 ERA and 108 strikeouts in 111 2/3 innings with Biloxi prior to his injury and returned with a strong outing Monday. Perhaps more important, he had limited right-handed hitters to a paltry .188 clip.
Cardinals
Andrew Knizner, C, Cardinals' No. 6
Carson Kelly might still be viewed as the catcher of the future, but Knizner has shown he can handle upper-level pitching, both as a hitter and receiver. He's hit .315 and posted a .373 OBP in Double- and Triple-A this season, par for the course for this career .310 hitter.
Cubs
Duane Underwood, RHP, Cubs' No. 9
Underwood impressed the Cubs in a June spot start and with his improved consistency, focus and health all season. He has the stuff and flexibility to help Chicago in a variety of roles.
Pirates
Mitch Keller, RHP, Pirates' No. 1/No. 12 overall
The overall Triple-A numbers (5.31 ERA in eight starts) don't look great, but Keller's still missing a lot of bats (10.0 K/9), and over his past three starts spanning 17 innings, he's allowed just three runs on 11 hits, walking five while striking out 15. That's a 1.59 ERA and 0.94 WHIP for those scoring at home.
Reds
Jimmy Herget, RHP, Reds' No. 13
The Reds' top prospects are either farther away or hurt (Nick Senzel, for example), but Herget deserves a chance to show what he can do in the big leagues after striking out nearly 10 Triple-A hitters per nine innings in 2018, right in line with his 10.7 K/9 career mark.
NL West
Diamondbacks
Taylor Widener, RHP, D-backs' No. 3
The D-backs got Widener from the Yankees in February's Brandon Drury deal, and he's gone out and led the organization in strikeouts while standing second in ERA. He was a reliever in college, so having him help out the bullpen short-term could be a fit.
Dodgers
Alex Verdugo, OF, Dodgers' No. 1/No. 28 overall
Verdugo would be starting for most clubs but hasn't been able to find a role on a talented Dodgers club. One of the best pure hitters in the Minors, he has batted .280/.345/.440 in two brief stints with Los Angeles earlier this year and definitely will be back in September.
Giants
Chris Shaw, OF, Giants' No. 5
Shaw has led all players in the Giants' organization -- in the Majors or Minors -- in home runs in each of the past two seasons. He could be in the running for a starting job in 2019, so a callup would make a lot of sense.
Padres
Francisco Mejía, C/OF, Padres' No. 3/No. 21 overall
Acquired from Cleveland for Brad Hand and Adam Cimber on July 19, Mejia has resumed catching full time since joining the Padres' system and continues to swing a hot bat for playoff-bound Triple-A El Paso. While it's still unclear how the 22-year-old backstop fits in long-term with regards to the defensively gifted Austin Hedges, the time has come to see what Mejia has to offer as a big league catcher.
Rockies
Brendan Rodgers, INF, Rockies' No. 1/No. 6 overall
Currently sidelined with a hamstring injury that isn't considered serious. Rodgers is capable of playing second base, shortstop or third base. Nolan Arenado and Trevor Story have been the Rockies' two best hitters, but D.J. LeMahieu has slumped this year and Rodgers could provide more offense.