I don't think that makes much sense at this point. Surely if we buy another CB now it has to be someone who is better then every CB at the club. If we buy Maguire to sell Smalling and Jones just so Lindelof gets to play, we are not strengthening the squad.
Maguire would first be an upgrade on Lindelof and Rojo if anything and if Tuanzebe plans to be our CB he should be fighting off bigger challengers than the likes of Maguire, Lindelof and Rojo. I think he is good tho, but he seems a bit overrated here right now, and i don't see a big reason to get him. Ok, it seems tempting to maybe replace Jones and Rojo with him and another top defender, but buying 3rd defender shouldn't be priority right now