The Portuguese boss faced the media on Thursday afternoon at Carrington ahead of the Leicester City clash at Old Trafford tomorrow.
Rooney has come under fire from fans and former players after a string of poor performances for Man United.
Speaking about the Englishman, Mourinho stated he wasn’t solely to blame for the three matches they lost in a week.
“We all started well, we all won four matches, and we all lost three matches in a week, so that is not [just] Wayne Rooney.
“To be honest he did not even play against Feyenoord, so he was directly involved in the last two matches.
“We had a very good start to the season, better than we expected and prepared for, and we were guilty of raising the expectations of the people and then we lost three matches in a row.”
After losing to Manchester City, Feyenoord and Watford within a week, his squad ended their loss streak against League One club Northampton.
The poor showings have raised questions about the ability of his squad and Rooney has taken most of the criticism as one of the poorest performers on the side.
He has not scored since the opening day of the season and has looked out of sorts in the midfield and upfront, but Mourinho doesn’t seem to agree and has dismissed claims that his captain is past it.