If 19 pounds comes from end of season weight to Spring Training weight that isn’t as drastic as it sounds. I don’t know what an MLB player would lose over the course of a season but ten pounds isn’t unreasonable
So if player X was 210 lbs at ST 2023, finished the season at 200 lbs and came into ST 2024 at 219 he could have technically gained 19 lbs but the reality is it’s closer to 10 when you look year over year