Garrett Mitchell, due to his high strikeout profile, high speed and his potential raw power is a very difficult player to compare, as most players would fail in the big leagues with this skill set. However the speed he has allows him to beat the infield with regularity, steal bases and provide such quality defense in centre field that it considerably improves his floor, and his ceiling could be similar to a Keston Hiura that can play defense. Given the thorn in the side Harrison Bader has been for the Brewers, a player who thrives on big moments, electric in the field and on the base paths, it could be a very similar player to what we have in Mitchell.
In Bader's first full season with the Cardinals, and produced a slash line of .264/.334/.422 for an OPS of .756, along with a BABIP of .358 and a strikeout rate of almost 30%. Due to his outstanding defense, he produced 4.1 fWAR in 2018, which may not be as unreasonable an expectation for Mitchell as it sounds. The following season, the height of the juiced ball era, he brought just a .680 OPS and still almost reach two WAR in 400 PA's.
Looking back to 2018 and his review on prospects1500.com, he was given the following detail:
As you can see, even in season with a WRC+ in the 80's, and with less than everyday players PA's, he's still provided enough value in terms of WAR to the team through high defense, and when he hits roughly league average, his fWAR loiters around three.
He also picks up his fair share of injuries, part of the reason he has limited PA's, and something Garrett Mitchell is likely to also have to contend with in the coming years.
He does however have very low exit velocities, just 83.4mph on average last season, and walk rates around 5-7% which is something Mitchell seems to do much better.
When drafted, Mitchell was considered a steal for the Brewers due to his raw power, his electric speed and defense, only dropping down because teams were concerned about his type 1 diabetes and the effect that may have on him as a professional.
He hasn't spent a whole lot of time in the minor leagues, through injuries and the missed 2020 season, in fact only having 472 PA's among Milwaukee's affiliate teams. He did develop as he moved up, with a low of 21.2% strikeout rate at AAA. He's got plus power when he gets the ball elevated but his swing does seem geared towards a more ground ball oriented profile. As a left hander, this might not be ideal, even with his speed, but he hit predominantly up the middle and to opposite field in his short stint in the majors last year, and can beat out infield throws with some regularity. I don't think anyone expects him to repeat his slash line from 2022, but it's very likely that as he adjusts to major league pitching, or even just professional baseball, his strikeout rate should drop significantly.
He likely has less of a hit tool than Bader does, but his speed both to 1st and on the base paths is a lot more obvious. He stole 8 bases in 68 PA's last season, whereas Bader has at most managed 17 in a season (last year with the Yankees). Mitchell recorded the fastest home to first time last year at just 4.01 seconds, and a regular ability to turn easy singles into doubles, and I can see his base running being a prolific weapon, especially with the new rules coming into force regarding pickoffs. For comparative purposes, Esteury Ruiz had a sprint speed of 29.8 ft/sec.
Combined with his power when he can elevate the ball, Mitchell has the ability to be a 20 HR/50 SB type player, but in all likelihood, I think in the coming season he's more likely to be 12-14 home runs and 40 stolen bases, still considerable numbers, and something that could make a big big impact on the brewers offense. He's currently projected by ZIPS for a .250/.320/.378 slash line and 98WRC+, which could make him a 3 WAR player given his skills outside the batter's box.
in conclusion, Mitchell seems a slightly more unpredictable version of Bader, with more speed, slightly better defense (in part as a result of this, and his plus arm), yet more swing and miss in his profile, and both of them have remarkably similar ground ball percentages. Both are electric and exciting to watch, with highlight reel efforts and energy that can draw in the crowds. I can't wait to see what 2023 has in store for Mitchell. He's picked up quite well in spring training (not that that's usually an indication) but appears to be lofting the ball with more regularity.