I wouldn't take McCalvy's article at face value, fwiw, as I find it incredibly hard to believe that a professional baseball player did absolutely nothing in the off-season to stay in shape other than "chase his kids around". I'm sure he worked out in some form behind the scenes, and the "chasing the kids around" was more of a comment in jest.
Also, he was not "subpar" at the plate in 2021. He was around league average to slightly above average with a 103 OPS+ and a 3.2 fWAR. Combined with his typically stellar defense and baserunning, that was more than enough production from him when healthy. The problem really started this year, when his power completely vanished and he turned into a below replacement-level player.