Once upon a time (just two years ago!), Cody Bellinger was one of the best players in baseball on one of the best teams in baseball. Through the Dodgers outfielder/first baseman's age-23 season, he had posted 15.0 WAR, with a 2019 figure of 7.7 WAR leading to a National League MVP. It was one of the best seasons by a player age 23 or younger in baseball history -- ranking among the top 50 by WAR on a list that includes, over the past 30 years, Mike Trout (four times), Alex Rodriguez (twice), Mookie Betts, Ken Griffey Jr., Albert Pujols, Bryce Harper, Grady Sizemore and Troy Glaus.
If you're waiting for the but, brace yourself because it's a hefty one. Bellinger regressed heavily in a pandemic-shortened 2020, then this year he was the third-worst position player in baseball (-0.8 WAR, ahead of only Jackie Bradley Jr. and the since-released Gregory Polanco) and the second worst at the plate (48 wRC+; Bradley Jr.), minimum 350 plate appearances.
He re-upped with the Dodgers just before the lockout for $17 million (news broke recently), a meager and basically compulsory raise from his 2021 salary of $16.1 million. He'll go through arbitration just one more time, then become a free agent after the 2023 season, so the ship needs to be righted soon to justify his salary and contribute to the next Dodgers playoff squad.
You can pull up Bellinger's awful surface numbers to see what happened, but there isn't much there: He's just way worse at everything, somehow.