London - Manchester United manager Jose Mourinho has acknowledged England left-back Luke Shaw is enduring a testing period in his Old Trafford career due to illness and injury.
Shaw, 21, spent most of last season recovering from a double leg break sustained in September 2015 and has made only 12 starts since Mourinho succeeded Louis van Gaal in the close season.
Despite reports Shaw could be on his way out, Mourinho gave no indication that United are open to offers for him, but he did concede the former Southampton player is having a tough time of it.
Asked if Shaw's history of injuries was counting against him, Mourinho replied: "Of course. You try to have in the squad the players with more minutes, the players in better shape, in better condition.
"In Luke Shaw's case, even in the (FA Cup) game against Reading, when he could have started the game and had 90 minutes, in the morning of the game he was ill and not ready to play.
"So even in that match, which could have been good for him, he was not able to play, so he's having a difficult period."
Shaw's fortunes contrast with those of Marouane Fellaini, who appears to have won over his critics, having been booed by his own supporters after conceding a costly penalty at Everton in early December.
The Belgium midfielder scored a valuable goal in United's recent League Cup semi-final first-leg win over Hull City and helped set up a late equaliser in last weekend's 1-1 draw with Liverpool.
His improved displays have prompted United to grant him a one-year contract extension.
"I think the fans turned back in his favour after he went back to good performances," Mourinho told reporters at United's training base west of Manchester on Friday.
"He's showing great character and the fans are showing great respect and great knowledge about his contribution."
Mourinho backs diving punishments
Mourinho added: "In the last matches he has been very important for us. He played very well the last match he started, coming in and being important in other matches in the last 20, 25 minutes.
"He's contributing well and he's a player who can be very useful. He can be more positional and more defensive. He can be more offensive and an extra man in the opposition box.
"He can be dangerous there. With me, he started the season and played some matches as a positional midfield player.
"In late matches when the team needed a goal, like against Middlesbrough, Liverpool, Hull City, he was playing in more offensive positions.
"He's a player who has a good understanding of the game and now I know him better than before, I know where he can help the team."
Mourinho also added his support to the idea, currently being explored by the Football Association, of introducing retrospective punishments for diving by players.
But the United manager believes any such decisions must be handled with consistency.
"I agree totally," Mourinho said. "But again I'm always afraid that for similar situations, (there will be) different decisions – inconsistency. I'm always afraid of that.
"But I would agree totally. It's like the interpretation of handball/balls to the hand, deflection/no deflection; the referee's analysis is not consistent.
"Then for similar decisions (situations), you have different decisions. But of course, yes, I would like retrospective action for simulation in the box."
United are sixth in the Premier League table, four points off the Champions League places, ahead of Saturday's trip to Stoke City.