I think that hurts miami at this point honestly.
Shows their desperation for some type of defensive presence against KG. Even if Bosh is not 100% healthy, they probably believe that his presence can still make an impact on KG getting all those touches, and scoring easy baskets. No one can outreach KG but Bosh. So in their minds, they probably will have him there just to slow down KG.
But in KG's head, he's never one to back down, or let someone slow him down. And know Bosh has been out for like 3 weeks, with an abdominal strain, he'll definitely take complete advantage of that. He already own Bosh when he's healthy. I'm pretty sure he'll own Bosh at 50%.
And also, maybe they need Bosh to take the load off of Wade & LBJ. And they won't be double teamed anymore.
Those are the only reasons why I can see why they're putting Bosh back for game 5. In my opinion its stupid, as he can re-injure himself. And if they really believe they can get to the Finals, they'll be without Bosh again.