Having made 18 league appearances last season, the 32-year-old appears to have no future at United and has been training with the reserve team after Mourinho confirmed that it would be "very difficult" for him to play for the club again.
The transfer window closed with Schweinsteiger still with United, although his chances of featuring under Mourinho appear slim, particularly after he was overlooked for the 27-man Europa League squad released by UEFA on Saturday.
United have included teenage defenders Timothy Fosu-Mensah and Axel Tuanzebe as they look to qualify from Group A, which also contains Feyenoord, Fenerbahce and Zorya Luhansk.
They begin their campaign away in Rotterdam on Sept. 15.
Schweinsteiger made his final appearance for Germany in a 2-0 friendly victory over Finland in Moenchengladbach on Wednesday after announcing his retirement from international football in July.
(Reporting by Ed Dove)
