It always makes me laugh when morons come out with shite like that. I have heard suggestions for Maguire, Wan Bissaka and Lindelof to play in midfield from them, and the guys who say it are always being 100 per cent serious and believing they're being tactically astute.
First of all, playing in midfield is a whole other ball game from defence. In defence you have the game in front of you, yes there is pressure from strikers, but a midfielder has to receive the ball, often on the turn, and pass between a congested area of the pitch, as well as orchestrate and control the game. It is a completely different ball game. I heard them say AWB can play there cos he can tackle and is fast, as if athleticism and tackling ability are the only considerations for a midfielder. The best midfielders rarely slide tackle, they intercept and have great positioning (rodri, Busquets). Wan Bissaka, Lindelof and Maguire are all technical lepers with low football IQ and little to no short passing ability and who would all be torn to pieces in central midfield.
Think of it this way. Real Madrid experimented with Sergio Ramos in midfield for a while, a much more technically talented player than the above. And he struggled big time in there. But they think guys like Maguire can do it.
I honestly hope that guy is taking the piss because it is frightening that someone who follows football as a fan and presumably has been for years could be that tactically clueless and oblivious.