I’d just get him back and give him some minutes. Can’t do him any more harm, and feck knows we need bodies in centre mid currently. What with 40 games in 3 weeks. Or something.Onomah seems to be in the unfortunate position of having to play for Steve Bruce for a second season running. That's assuming that Bruce is appointed in the next week or so. Who knows, he may somehow impress under Bruce, but I doubt they will suddenly turn into the type of team the Josh would thrive in.
I also agree with Windy that a move away would be best for him.