"To overhaul the squad" means to make significant changes or improvements to a group of people, typically a sports team, to make it better and more effective. Full definition
Depends what your definition of overhauling the squad is? (justarsenal.com)
Spuds succeed overhauled their squad in 2 years under Pocchetino. (justarsenal.com)
I believe the board will move wenger upstairs this summer but the club needs either a top manager who spend day 100m on 3 players and gets the rest to perform better or a top Manager to completely overhaul the squad but that will take 300m I don't believe the club are willing to spend either, so I think it will be a up and coming manger who will eventually fail. (justarsenal.com)