Aaron Judge and Shohei Ohtani might be the headline performers of the season, but this year's rookie class is the best in decades, boasting seasons of 4.8 to 5.1 fWAR by Julio Rodriguez, Adley Rutschman, Spencer Strider and Michael Harris II.
Any of those seasons would've been the best rookie performance since Judge in 2017; meanwhile, Strider has posted the most rookie pitcher WAR since Hideo Nomo's magical 1995 season. The last season with two rookies having WAR of 4.8 or higher was 2001, when Albert Pujols (7.2 WAR) and Ichiro Suzuki (6.0) took the league by storm.
Even better, eight of the top nine rookies by WAR this year will be in the playoffs, with the only exception Rutschman, whose Baltimore Orioles will finish at least .500. That could be a sign to noncompetitive teams to call up their best young talent as soon as possible.
Here's my ranking of the top 10 rookies who will be in the upcoming postseason, based on the impact I think they'll make in October.
1. Julio Rodriguez, CF, Seattle Mariners
Rodriguez's power and speed combination is one of the best in the league: He's in the top 2% for maximum exit velocity and top 3% for sprint speed, per Baseball Savant.
2. Michael Harris II, CF, Atlanta Braves
Rodriguez was third on my Top 100 entering the year and a leading candidate for Rookie of the Year, so his season was somewhat expected. Harris, on the other hand, was ranked 38th and, though I was the highest one on him out of my fellow media members, even I didn't think he'd spend much time in the big leagues. But here we are, with Harris nearly matching Rodriguez in WAR.
Harris is in the top 6% in sprint speed and top 8% in overall defense in center field, which matches the preseason scouting reports. The surprise this year has been his offense, with both his power and contact ability outpacing the rosiest projections: He's hitting .298 with a shot to go 20-20 after completely skipping Triple-A and playing only 43 games in Double-A -- all this season.
3. Spencer Strider, RHS, Atlanta Braves
While we're talking about surprising Braves prospects, Strider wasn't even on the Top 100. I went to Rome, Georgia, last year specifically to watch both Strider and Harris. Strider is still showing the same upper-90s fastball (averages 98.2 mph) with bat-missing characteristics and an aggressive style, but his slider and overall execution took a big step forward this year. I thought he'd be a multi-inning threat who could be used in multiple roles, maybe like a fastball-reliant Lance McCullers in a great outcome. For reference, Strider's rookie season is better than McCullers' best season, so he has blown career projections out of the water at age 23.
The scouting report held up a good bit in one area: Among starters with over 100 IP this year, Strider is throwing his fastball the most of any of them at 65.6% of the time, and it's been the second-best fastball in the sport, per StatCast.
4. Steven Kwan, LF, Cleveland Guardians
Kwan was a marginal prospect at Oregon State as an advanced hitter with a great approach but no other above-average tools, eventually going late in the fifth round in the 2018 draft. He had a breakout 2021 season in the upper minors, hitting 12 homers and looking like there was enough punch to let his offensive skills play at the big league level.
Well, it worked even better than I expected after ranking him the 123rd prospect in baseball entering the season. Kwan has hit .301/.375/.403 with 19 stolen bases and 4.3 WAR, buoyed by the elite defense, primarily in left field (+15 runs per DRS, or fifth best among all outfielders). He's a classic type of player whom WAR appreciates more than a fan or even scout would after one game because of his wide base of contributions that are more subtle and less NFL-combine-oriented.
5. Jeremy Pena, SS, Houston Astros
Like Kwan, Pena was somewhat limited as a college prospect, with real defensive value but unclear offensive projection. Unlike Kwan, Pena was big and strong with obvious upside if he could put the pieces together at the plate. Due to the COVID-19 pandemic and being a later-developing college prospect from Maine, he played only 182 career minor league games, hitting 18 homers and ranking 48th on my Top 100 entering the year -- due to the chance that things could click in a bigger sample for him as Carlos Correa's replacement.
They did in a big way, as he hit 20 homers this year in addition to ranking as the third-best defensive shortstop in the league per DRS at +14 runs and posting a sprint speed in the top 5% of the league. The concern in the playoffs is that Pena's chase rate at the plate could cause problems with slider-heavy pitchers in high-leverage games.
6. George Kirby, RHS, Seattle Mariners
If your eyes glaze over with the advanced stats, Kirby is your man. He doesn't stand out in those ways; he's a guy whose best quality is fastball command, which is easy to see but notoriously hard to quantify. Among pitchers with 120 IP, he has the fourth-lowest walk rate in the league and is still striking out a batter per inning. He's not a soft tosser (sitting 95.3 mph with his heater), but he's old-school in that he throws four pitches and still throws fastballs 57% of the time, which he can do thanks to pinpoint command.
7. Lars Nootbaar, RF, St. Louis Cardinals
Nootbaar was most notable for much of his professional career for a name that sounds like a popular Scandinavian snack. He took a step forward in 2021 and looked like he would be a solid extra outfielder; but then this year, he improved at nearly every part of his game in the kind of seemingly random occurrence that keeps evaluators on their toes. He has been above average defensively as a corner outfielder, he's now top 11% in average and maximum exit velocities, in the top quarter of the league in sprint speed, and in the best 7% in chase rate.
Add all of that together and you have a standout in the field, on the bases, in pitch selection and in power, which are basically the four things that teams care about most in evaluating position players. His season (2.5 WAR in 332 plate appearances, entering Sunday) extrapolates to a 4.1 WAR season if given the same playing time as Rodriguez. And Nootbaar's metrics suggest there hasn't been much, if any, luck in his outcomes this year; the Cardinals' development machine has done it again.
8. Andres Munoz, RHR, Seattle Mariners
Munoz was touching triple digits early in his professional career and that's still his calling card, but he's now much more well-rounded. Munoz is averaging 100.2 mph on his heater but now has a standout slider that he's throwing 65% of the time. Imagine being able to throw 100 mph whenever you want and two-thirds of the time deciding not to -- his slider is now that good. It's the second-best slider in baseball, just a hair behind Edwin Diaz's. Said another way, 51% of swings at his slider are whiffs, also putting him just behind Diaz.
9. Brendan Donovan, 2B, St. Louis Cardinals
Donovan was overshadowed entering the year by higher-profile infielders in the Cardinals' system like Nolan Gorman, Jordan Walker and Masyn Winn, while the big league team is anchored by MVP candidates on the infield in Nolan Arenado and Paul Goldschmidt, along with five-win player Tommy Edman. Donovan was even overshadowed in his 2018 draft year at South Alabama by teammate Travis Swaggerty, who went 10th overall to Pittsburgh while Donovan went in the seventh round to the Cards.
I ranked Donovan 14th in the system entering the year, seeing him as a hit-over-power utility type with defensive value mostly on the corners. He has been a bit better with the glove than I thought he would be, and his excellent approach has translated much better and more quickly at the big league level than I expected. He's not a cornerstone-type talent like those other Cardinals mentioned above or many of those ranked ahead of him, but he has quickly proved to be one of the best young hit/approach combos in the league, so he looks set for a long career.
10. Oswaldo Cabrera, RF, New York Yankees
Cabrera was never really a Top 100 prospect type and doesn't have the frame or speed to make scouts swoon like those at the top of the list, but he really has learned to make the most of his skill set. He's a power-over-hit type who has figured out how, using ideal types of contact, to produce 25-ish homers the past two seasons with pretty ordinary raw power for a big leaguer and enough contact to avoid becoming a Ryan Schimpf-type. He's also a versatile, valuable player who came up as a primary second baseman but can play capably anywhere on defense other than pitcher or catcher.