Thomas Tuchel delivers worrying Kobbie Mainoo injury update to spark Manchester United concern

Mainoo had yet to play a minute at the tournament and was expected to get a run-out in Miami, but was once again left off the team sheet.And Tuchel has now issued a more detailed update on the player’s condition, explaining he had picked up a back problem in training.“Kobbie was injured in the last training session (on Friday) morning,” Tuchel said of the 21-year-old on Saturday. “He had a sharp pain in the back within the training and he was not ready to play.”Countless supporters have lamented Mainoo’s absence throughout the World Cup. He finished the Premier League season in impressive form under Michael Carrick and appeared in pre-tournament friendlies, but did not feature at all in the World Cup proper despite Declan Rice’s struggles.Injury worry: Kobbie MainooPAMainoo himself appeared unimpressed with his role in the squad. He cut a dejected figure throughout the tournament and was often the first to leave the dressing room after England matches, returning to the team bus with his hood up and headphones on.He was in attendance at England vs France in spite of his injury.Carrick and Manchester United will now be sweating over the player’s fitness as they gear up for what is sure to be a demanding season, which will see them return to the Champions League.Following some time off, Mainoo will return to Carrington as part of an overhauled United midfield which has been bolstered by the additions of Youri Tielemans and Andrey Santos, signed for around £85m in total.Read MoreUnited were beaten 1-0 by Wrexham in their first pre-season friendly of the summer on Saturday.