I'll be very happy to see Theis back. If he can stick the 3 for a decent percentage I think he'll be a big help. With Horford and Morris gone there are real minutes and shots available at the 4 and 5 positions for somebody. I expect Theis, Ojeleye, and GWilliams to compete aggressively.
As for those dismissing Theis; I think Yabusele is the guy who's salary and roster spot are no longer justified. Time to move him, maybe with a 2nd conditional and some cash, into someone else's cap space. Boston needs the 3M for other things.