Id bring back Micah when Villa go down. I know he has had injuries this season but he's been fit for the majority of the season. Would basically count as a free player with his homegrown status and can provide cover at both centreback and fullback.
With Kompany's injuries, we've got a dilemma next season, do we go into the season with 4 centre backs and hope Kompany can play his part, or do we have to effectively replace him by bringing in a 5th centre back? That's going to leave us short elsewhere and if Kompany is fit, it's going to cause unrest with lack of game time. Having Kompany Otamendi Mangala Denayer and Micah as cover next season would work well i think.
Unlikely i know, but i don't see many better options right now, especially where the champs league squad is concerned.