The 30-year-old Republic of Ireland international will head back to England tomorrow after tweaking a muscle during his debut for the club against Arminia Bielefeld on Sunday.
O'Shea will be unable to play in the remaining games against Hannover 96 and Borussia Monchengladbach, and that means there is little point in him staying with the rest of the squad.
Flat out: O'Shea's pre-season tour has been cut short
Manager Steve Bruce told the club's website: 'There's no point in taking risks during pre-season.
'John isn't going to play against Hannover or Monchengladbach, so we thought it would be easier if he flew home early to rest up and he can come back stronger when we return from Germany.'
No risks: O'Shea will not be forced into action so close to the start of the season
CLICK HERE TO SIGN UP FOR OUR FREE FANTASY FOOTBALL GAMESunderland eye African exposure after agreement with Ghanaian club Asante KotokoHe couldn't trust them. Fergie accuses Sunderland over breakdown in Gibson moveAll the latest Sunderland news, features and opinion