It felt like everywhere you looked in 2023, rookies were making key contributions. Johan Rojas was covering acres of ground for the Phillies. Corbin Carroll and Brandon Pfaadt were speeding around the bases and making clutch starts respectively for the D-backs. And perhaps most famously, Evan Carter was on the run of a lifetime to help the Rangers (and his fellow rookie slugger Josh Jung) bring a World Series title to Texas.

Rookies aren’t just happy to be in the Octobers of their first seasons anymore. They’re expected to be key contributors to contending clubs right from the start of their careers. This year’s group is no different.

Here is a ranking of 10 rookies expected to have the biggest impacts on this year’s Major League postseason:

1. Jackson Merrill, OF, Padres
It could be a coin flip between the Jacksons at the top of the list, but we’ll lean toward the one who was more consistent throughout his entire rookie campaign. Merrill led rookie hitters in hits (162), extra-base hits (61), home runs (24), average (.292), slugging percentage (.500) and total bases (277). And that’s only considering his offense. The 21-year-old moved to center field for the first time in the spring and proved to be a defensive asset as well. He’ll be a big part of San Diego’s chase for its first World Series title.

2. Jackson Chourio, OF, Brewers
There might not be a more dynamic player on this list. After getting off to a slow start, he slashed .303/.358/.525 over 98 games from June 1 onward. The 20-year-old finished the season with 21 homers and 22 steals, making him the only 20/20 rookie of this year’s class and the youngest 20/20 player in Major League history. His top-of-the-line speed makes him a quality outfield defender in the corners as well, and this playoff run could give him a national spotlight as one of the game’s best five-tool talents.

3. Colton Cowser, OF, Orioles
The Jacksons above may get most of the (deserving) pub, but Cowser’s offensive season shouldn’t be overlooked. He finished tied with Merrill among all rookies with his 24 homers, finished second with 120 wRC+, was fourth in total bases (223) and tied for fourth in extra-base hits (51). The Orioles had one of the most potent offenses in the American League during the regular season and they’ll need Cowser’s pop in the back half of the lineup to help them score runs all postseason long.

4. Luis Gil, RHP, Yankees
When Gerrit Cole was sidelined for the first two-and-a-half months of the season with elbow inflammation, Gil picked up the slack by going 8-1 with a 2.04 ERA in 13 starts during his absence. After losing most of 2022 and 2023 to Tommy John surgery, he rebounded this year to lead all rookies in wins (15), starts (29) and average-against (.188, minimum 100 innings) while ranking second in innings (151 2/3) and strikeouts (171), third in strikeout percentage (27 percent) and fifth in ERA (3.50, minimum 100 innings).

5. Kyle Manzardo, 1B, Guardians
Manzardo slashed just .207/.241/.329 in 30 games during his first taste of the Majors in May and June, but he returned in September and was one of Cleveland's most productive hitters in the final month. He showed why he was regarded as one of baseball's best first-base prospects before he graduated, with his combination of hitting ability and power translating into a .270/.333/.540 line with five homers in 23 contests.

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6. Austin Wells, C, Yankees
Wells had the best 2024 season of any rookie catcher, hitting .229/.322/.395 with 13 homers in 115 games while supplanting Jose Trevino as New York's starter. Though scouts questioned his defense throughout his Minor League career, he proved more than capable in the Majors, scoring well in framing and blocking metrics while throwing out 26 percent of would-be basestealers.

7. Spencer Schwellenbach, RHP, Braves
After his outstanding start on Monday in the first game of the doubleheader against the Mets, we likely won’t see Schwellenbach unless the Braves beat the Padres in the Wild Card series and advance to the NLDS. He’s been a huge reason why the Braves were able to weather the storm of losing Spencer Strider, finishing among qualified rookie leaders in a host of pitching categories: second in BB/9 (1.67) and K/BB (5.52), third in WHIP (1.04), fifth in ERA (3.35) and BAA (.226) and tied for seventh in K’s (127).

8. Tobias Myers, RHP, Brewers
After spending seven years in the Minors across seven different organizations, Myers made his Major League debut with the Brewers at 25 years old on April 23 and didn’t look back much. He became one of Milwaukee’s most reliable starters with a 3.00 ERA, 1.17 WHIP and 127 strikeouts over 138 innings. Myers throws as many as six pitches (four-seam, sinker, cutter, slider, changeup, curveball) to keep hitters off balance, and his control was impressive with just a 6.3 percent walk rate. The Brewers used Myers as a bulk pitcher behind an opener in his final regular-season outing on Sept. 28, and they could choose to go that route again in October.

9. Joey Ortiz, 3B, Brewers
Acquired from the Orioles in the Corbin Burnes blockbuster in February, Ortiz essentially matched expectations in his first year with the Crew, serving as a league-average bat (.239 average, 11 homers, 104 wRC+) while providing stellar defense on the dirt. With Willy Adames at short, Ortiz took over duties at the hot corner. He tied Matt Chapman for the MLB lead among third basemen with 11 Outs Above Average while proving adept at coming in and moving to his right. If pitching and defense wins championships, Ortiz can give Milwaukee a leg up there, and his above-average bat speed could help him contribute offensively in a big moment too.

10. Parker Meadows, OF, Tigers
Meadows’ speed (92nd percentile in MLB) and defensive range in center field (90th percentile) would be enough to help him make an impact in Detroit’s continued Cinderella run to and through October. But the 2018 second-rounder has shown something with the bat lately too, slashing .296/.340/.500 with six homers in 47 games since returning from a right hamstring strain on Aug. 3. Still, don’t be surprised if his biggest highlight of the postseason is a homer he robs with a stellar catch (like his Aug. 7 leap against Seattle), rather than one he hits himself.