The odds of any of these guys playing a single meaningful minute in the 2025 playoffs is so remote IMO, that I wouldn't even figure it in.
The regular season should mean nearly nothing to the Celtics. I'd be surprised if any of those non-rotation minutes, which is what I'd consider any minutes those guys get, would go to Walker over the guys they have rights to going forward.
They need to find out if Springer can get to a rotation level player by this years deadline, otherwise they likely have to dump him to save Wyc, or Irv I guess, cash. Secondarily, they need to find out if Baylor and/or Walsh can step into a rotation role in 2025-26, and force feeding them minutes would be helpful i that goal.
Walker is young, but he's had lots of opportunity to play and hasn't shown much improvement. The guy has gone from his rookie deal, to signing a one year deal at the mini-MLE, to signing one year at the minimum, to signing an exhibit 10 camp deal after Ron Harper Jr. and Tristan Enaruna.
Maybe the whole league is wrong on him, but it seems unlikely to me.