You now have the ability to “lock” players in their roster.
If a locked player is in your lineup, and you obtain a better player, the locked player will remain in the lineup.
Similarly, a locked player cannot be cut or otherwise removed from the roster as a whole.
To view your players to lock or unlock them, go to the TEAM tab at the bottom of your screen, choose either the BATTERS or PITCHERS tab at the top of the screen, Each player displays a lock icon in the top right of their profile. Tap to lock or unlock.