Lingard came off against Barca in the second-half.
He looked to be in discomfort as he made his way to the sidelines.
But Mourinho isn't concerned.
He says the England international was just suffering from fatigue in United's 1-0 defeat to the Spanish giants.
"No problem with Jesse," Mourinho said.
“I think it’s just muscle tiredness.”
Despite the defeat to Barcelona, Mourinho is upbeat about his side's pre-season work.
“I am very happy,” he said.
“No injuries, because Mata and Herrera in this moment I don’t think we are speaking about injuries.
“I think next Saturday it will be no problem to be back to training.
“So no injuries, a fantastic atmosphere, a fantastic work ethic, great organisation.
“So now we just need to land safely in Manchester and this part of the pre-season is perfect.”