Jackson Merrill never played a game above Double A when he made the Padres’ 2024 Opening Day roster at 20 years old.

Merrill, who turned 21 during his first month in the big leagues, went on to finish second in the 2024 NL Rookie of the Year voting after batting .292 with a .326 on-base percentage, .500 slugging percentage, .826 OPS, 24 homers, 31 doubles, six triples, 90 RBIs and a 4.4 bWAR in 156 games.

But transitioning to the majors for rookies age 20-22 without any — or limited — Triple-A at-bats isn’t as simple as Merrill made it look.

The Red Sox have two 2025 AL Rookie of the Year candidates, 20-year-old  and 22-year-old , who could be asked to make a similar leap this season.

MLB Pipeline polled front office officials to find out their top 2025 AL Rookie of the Year candidates. of the vote each. Campbell received the fifth highest percentage (8.5%).

Campbell, who has appeared in just 19 Triple-A games, will compete for the Opening Day second base job if the  or via trade. “Team officials seem increasingly comfortable with the idea of Campbell opening the season in the big leagues — whether at second, in the outfield, or as a versatile contributor.”

Is what Jackson Merrill did — 24 homers, .500 slugging percentage, .826 OPS, etc. — a reasonable expectation or close to realistic for Campbell and Anthony this year?

It’s possible as Merrill and others (examples below) have showed but the team and fans shouldn’t expect that type of production in Year One.

Although they both impressed after late-season promotions to Triple-A Worcester last year — Anthony had a .983 OPS and Campbell an .898 OPS — they have combined for just 249 Triple-A plate appearances.

Big league pitching is nastier than ever right now. ran a story showing how average fastball velocity increased from 91.9 mph average in 2008 to 94.2 mph in 2023. With the evolution of the sweeper as well as spin and break being better than ever, it’s harder than ever to hit. It makes the gap between Triple A and majors more much larger than a decade and a half ago.

Rookies 22 and under last season combined to bat .244 with a .304 on-base percentage and .391 slugging percentage in 6,739 plate appearances. They slugged .401 in 2023 and .387 in 2022.

Overall last season, rookies of all ages combined to bat .233 with a .298 on-base percentage and .371 slugging percentage in 27,746 plate appearances.

In 182,449 plate appearances league-wide in 2024, hitters batted .243 with a .312 on-base percentage and .399 slugging percentage.

So the rookie numbers aren’t too far off from the league average.

Triston Casas, then 23, experienced the difficult transition in 2023 when he batted .184 with a .300 on-base percentage, .342 slugging percentage and .642 OPS in his first 49 games (180 plate appearances) through June 2.

It was his first full rookie season after appearing in 27 games at the end of 2022. He turned it around during the final four months and finished with an .856 OPS and third for the 2023 AL Rookie of the Year.

when some of these top prospects — including 22-year-old Marcelo Mayer — begin to break into the majors.

“I wanted to come up and carry the team and carry the lineup,” Casas said. “It bothered me when I wasn’t. But once I stepped back and realized there’s a learning curve and there’s other guys … that were there for me so I didn’t have to do that heavy lifting — that took the pressure off me and just let me be myself. It’s all about who’s supposed to be doing the damage in the lineup.

“It’s just about who at the time is supposed to carry the lineup,” Casas added. “I don’t think anybody expects a rookie to come up and tear the league up and just hit the ground running and carry our lineup. I think we’re going to lean on guys who are experienced.”

Baseball America ranks Anthony No. 2 and Campbell No. 4 on its Top 100 list. MLB Pipeline ranks Anthony No. 2 and Campbell No. 7 on its Top 100 list.

Five of MLB Pipeline’s top 10 prospects on its 2024 preseason Top 100 made their major league debuts last season. Four of them — Jackson Holliday, Jackson Chourio, Wyatt Langford and Dylan Crews — were position players. Merrill entered last season as MLB Pipeline’s No. 12 prospect.

Holliday, the No. 1 prospect on that list, is a cautionary example of why not to expect immediate results. Baltimore promoted him at 20 and after just 28 games and 117 at-bats at the Triple-A level between the end of 2023 and the beginning of 2024.

Holliday, who was approximately seven and a half years younger than the average age of an MLB player, recorded just two hits and struck out 18 times in his first 34 major league at-bats before the Orioles demoted him back to Triple A.

The Orioles recalled him later in the season. He batted .189 with a .255 on-base percentage, .311 slugging percentage, .565 OPS and 0.1 WAR in 60 games (208 plate appearances) overall.

Chourio, the No. 2 prospect, made the Brewers’ 2024 Opening Day roster at 20 with just six Triple-A games on his resume.

Milwaukee was spot on in its evaluation of Chourio’s readiness for the bigs. He batted .275 with a .327 on-base percentage, .464 slugging percentage, .791 OPS, 54 extra-base hits and 3.8 WAR in 148 games (573 plate appearances) on his way to a third-place finish in the NL Rookie of the Year voting.

Langford, the No. 6 prospect, made the Rangers’ Opening Day roster at 22 after appearing in just five Triple-A games at the end of 2023.

He showed Texas made the right decision. He finished seventh for the AL Rookie of the Year and batted .253 with a .325 on-base percentage, .415 slugging percentage, .740 OPS, 45 extra-base hits and a 3.9 WAR in 134 games (557 plate appearances).

Crews (No. 7) debuted in August at 22 after 49 games (238 plate appearances). He batted .218 with a .288 on-base percentage, .353 slugging percentage, .641 OPS and 0.6 WAR in 31 games (132 plate appearances).

Junior Caminero (No. 4 on MLB Pipeline’s Top 100 list at the beginning of 2024) had already debuted in the majors as a September call-up late in 2023 at 20 years old.

The Rays decided to send him back to Triple-A to begin 2024 where he appeared in 53 games before the Rays promoted him Aug. 13 at age 21. He was Baseball America’s No. 1 prospect at the time and batted .248 with a .299 on-base percentage,.424 slugging percentage,.724 OPS, 16 extra-base hits and a 0.7 WAR in 43 games (177 plate appearances).

Also of note, Elly Da La Cruz, a top 10 MLB Pipeline and Baseball America prospect entering 2023, debuted at 21 in June 2023 after 38 Triple-A games (three more than Anthony has played in).

He showed some of his elite talent in 2023 but he became a true impact player in his second season. His OPS increased from .710 in ‘23 to .809 in ’24. His WAR increased from 0.8 as a rookie to 5.2 in his sophomore campaign.

So what does all this information tell us?

It really depends on the individual and more minor leagues and Triple-A games doesn’t lead to more success.

Campbell and Anthony have enormous talent but they can’t be relied on to jump in and make an immediate impact. A lot of patience might be needed as they adjust at such young ages and it should eventually pay off.