The German had been been exiled from the Man United first-team since Mourinho took over in the summer, but has been back in training with the squad during the week.
Schweinsteiger had also been linked with a summer move away from Old Trafford but turned down a move to Sporting Lisbon to fight for his career.
Speaking about his return, Shaw claims the players are delighted to have him back.
“It’s great to see him back,” he said.
“We found out the news a couple of days ago and it’s so great to have him back.
“He’s a big influence in the dressing room and obviously on the pitch, especially for the young players like myself.
“It’s a great boost for us, the experience and the quality that he brings. The quality he possesses is a boost for our team and I’m so glad to have him back.”
He was left out of United’s squad photograph released last week and supporters believed he’d never feature in a red shirt again.
Although we haven’t seen him on the pitch yet, it’s great to see the German all smiles amongst the rest of his teammates.