Ole Gunnar Solskjaer says a decision is still to be made over whether Marcus Rashford will undergo shoulder surgery before the start of the new season.
England forward Rashford was hampered by the longstanding problem throughout the 2020-21 campaign.
The 23-year-old is currently on holiday after making five substitute appearances for England at Euro 2020.
United manager Solskjaer, speaking after his side began their pre-season programme with a 2-1 friendly win at Derby, told Sky Sports: “We are reflecting. We have to make the best decision for him on what to do with his injury. We have still not decided what the course of action [is].”
Solskjaer also assured Rashford of his and the club’s ongoing support in the wake of the racial abuse he has suffered since his miss in the penalty shootout loss to Italy in last weekend’s Euro 2020 final.
The Norwegian said: “We will definitely support him, Man Utd fans and football fans will support him. Just having the courage to step up to take a penalty in such as game is a win in itself.
“The actions of some people are not reflective of the majority of football fans – or all football fans, [because] I don’t think they are football fans at all. Marcus is a strong boy mentally.”
Solskjaer also confirmed United were hoping to wrap up a deal to sign Borussia Dortmund’s England international Jadon Sancho.
“I don’t think it is a secret that we have made a deal with Dortmund,” he said. “We are working on it. There a couple of things [to complete] on the paperwork.”
Jesse Lingard appeared in the second half for United at Pride Park having returned to the club following his loan at West Ham in the second half of last season.
“Jesse is a Man Utd player,” said Solskjaer of the 28-year-old, who hit the woodwork. “He wants to fight for his place. He has come back bright, bubbly, loads of energy, confident.
“Everyone saw what he did towards the end of last season at West Ham. He is still in my plans.”
United won with goals from Birmingham-bound Tahith Chong after 18 minutes and his replacement Facundo Pellistri on the hour. Colin Kazim-Richards pulled one back for Wayne Rooney’s Rams 20 minutes from time.
Holland U21 international Chong last week secured a loan move to Championship side Birmingham but is remaining with his parent club for pre-season training.
Former England and Burnley goalkeeper Tom Heaton played the first half as he begins his second spell at United following his release by Aston Villa.
The 35-year-old caught the eye with a fine point-blank save from a Phil Jagielka backheel before making way for Lee Grant as Solskaer made wholesale changes for the second period.
Derby’s side featured former United trainee Ravel Morrison, who is currently on trial with the Rams.