The Red Devils coach has signed Eric Bailly, Victor Lindelof and Alexis Sanchez, since taking over from Louis Van Gaal back in May 2016, Naija News recalls.
Mourinho is planning to make one or two signings to strengthen his defence during the January transfer window.
Sutton has questioned why United board would even consider handing Mourinho a substantial transfer budget in January.
“He [Mourinho] signed Pogba, he signed Sanchez,” Sutton told BBC Radio 5 Live.
“His signings have been a disaster. He wants more money! How can they trust him?”