The benefits of playing him are
a) we can rest first choice players without it looking like we've fielded a weakened side (and upsetting the league), and he can help us keep our form going at the same time
b) he has a chance to earn a place in our playoff team (he hasn't been able to do much else recently, so the game time would help him get up to speed, if there's a chance he can play a part)
I reckon give him 30 mins or so. The longer he's on pitch the more chance of him getting injured, and he is massively injury probe.