Jose Mourinho is unhappy with the "cautious" recoveries of Chris Smalling and Phil Jones but insists they have a future at Manchester United.
The defenders have missed United's last seven matches in all competitions, with Smalling struggling with a knee injury and Jones having suffered a broken toe.
The United manager's frustration with their lengthy recoveries has led to speculation that both could be sold in the next transfer window.
However, when asked if they could be at Old Trafford next season, Mourinho said: "Of course they have. I hope this season.
"It's not just about them. It's about the philosophy and mentality around them. Cautious. Cautious. Cautious. Just a cautious approach.
"It's a profile, it's the philosophy of work. Just that."
Asked if modern players are less willing to take risks with their fitness in matches, Mourinho said: "Professional football at a high level? Yeah."
The injuries to Jones and Smalling, coupled with the losses of Zlatan Ibrahimovic, Marcos Rojo, Juan Mata and Paul Pogba, have left United facing a minor injury crisis for the derby at Etihad Stadium.
Mourinho, however, says the players at his disposal are showing in training that they are determined to fight for results in a crucial stage of the season.
"I think the fact that we are fighting for important things still is a good motivation to keep people together, to make people make an extra effort," said Mourinho, whose side travel to Swansea City on Sunday and Celta Vigo in the Europa League semi-final first leg next week.
"Wednesday's training session started at 3pm: I was here at 10:30am and when I arrived some players were already here, taking care of little details and taking care of their recovery. That is motivation.
"I think maybe opponents they look at us with different eyes because we don't have Zlatan and Paul and Marcos and Mata and Jones and Smalling.
"Maybe they look at us with different eyes but I think they are not stupid, they are not naive, and they know that we are going to give them a fight."