We are running the rule over the new United boss' options in each position and today take a look at the full-backs vying for first-team spots. Click on the player's name for their full profile.
Alex Büttner: Signed as cover for Patrice Evra, the tenacious Dutchman showed glimpses of great potential in his first campaign and even scored both on his debut and in the last game of Sir Alex Ferguson's reign.
Patrice Evra: Just when we thought we knew what we'll get from our left-back – top-drawer defending, amazing consistency, incredible fitness levels plus fortitude and focus – the Frenchman surprised everybody by netting a few goals last term.
Fabio: Spent the entire season on loan at QPR and was unfortunately unable to prevent Harry Redknapp's side from sliding into the Championship. United's right-back in the 2011 Champions League final will have learned plenty from the experience and makes a welcome return to the fold.
Rafael: The buccaneering Brazilian had his best campaign to date in a United shirt in 2012/13, making the right-back spot almost exclusively his property and catching the eye at both ends of the pitch, particularly with spectacular strikes against Liverpool and Queens Park Rangers.
Guillermo Varela: Snapped up from Penarol in Uruguay, the combative South American is on a steep learning curve but has already impressed during a trial spell spent training exclusively with the first-team group. Signed a five-year contract before heading out to Turkey for the Under-20 World Cup