Although he started in the EFL Cup, Rooney was dropped in the wake of United's 3-1 loss at Watford last month.
The England international understood manager Jose Mourinho's decision after his display at Vicarage Road.
"Listen, I had a bad game at Watford. I played bad, I know that and I understand that," Rooney said, via The Independent.
"I think if he was picking the next team on the back of that, I understand not playing. The team have done well, certainly in the Leicester game since that.