The former England international has only made one appearance for City this season which came in the final seven minutes their Carabao Cup victory against Huddersfield back in September.
Phillips will join the Championship side until the end of the season on a straight loan agreement with no option or obligation to make the move permanent in what is a move that could see him finally get back to his old self.
The former Leeds United star will need time to get up to speed after just one cameo for City and Guardiola spoke on the midfielder who he believes many are happy to see return to his former glory.
“He trained (in the) last days because he was injured in the previous.
“He needs minutes to recover his best. He has to play, he made some loans. How he is as a guy everyone is desperate for him to come back, play minutes and be at his best because he deserves it.
“Most of the times it was setbacks for injuries. He had long injuries - first with his shoulder then his knees, ankles, hamstring. Struggled with that but not just Kalvin but if you cannot play its more difficult.”
The 30-year-old still has more than two years left on his contract at the Etihad with his deal set to expire in 2028. If his loan is a success, the Blades may seek to sign him permanently in the summer.