Because he's under performing since coming back from his injury, so I don't see the point in playing him again until next season.
This doesn't make sense.
If he hasn't 100% fully recovered from his injury he needs games to regain match fitness and sharpness, that's the point of playing him so he's ready to go for next season.
It's like you're saying that every player who plays football should be playing at 100% otherwise there's no point in them playing.