It's not that he's necessarily the solution but he may be the lesser of two evils on current form. If Ten Hag is being fair here then he acknowledges that Lindelöf has been very poor and Maguire has earned an opportunity to get back into the team based on his last couple of performances. He may well get into the team and have an absolute mare, but as of right now I think it makes sense to give him the nod over Lindelöf.
Has he really been good lately? Everytime I see him I just feel nervous and pity the guy.