"To rebuild the squad" means to make significant changes and improvements to a group of people, often in a sports team, in order to make it stronger, more successful, and more competitive. Full definition
Any big name manager will ask about budget for rebuilding the squad during his interviews. (justarsenal.com)
But I would prefer a new manager with fresh insight with more ambition to invest the money rebuilding the squad rather than a 67 year old who will be gone in 2 years. (justarsenal.com)
The winter transfer window is finally over, a period in which Russian club's rebuild their squad due to the size of the break. (russianfootballnews.com)