Interim England manager Gareth Southgate has refused to comment on Jose Mourinho's apparent criticism of Luke Shaw and Chris Smalling.
Smalling has missed Manchester United's last four games with a foot injury, while Shaw spent the vast majority of last season on the sidelines with a broken leg and has suffered discomfort at times this season.
Mourinho seemingly questioned the bravery of the pair following his side's 3-1 win over Swansea City on Sunday, but Southgate - who left both players out of his squad to face Scotland and Spain - believes that each case should be treated individually.
"Chris hasn't played for quite a while and Luke has played but we've known he's had ongoing difficulties coming back from a very serious injury," he told reporters.
"Our medical teams - as with all the clubs - have been liaising very closely throughout the week [with United]. The decision with Luke was a bit later but we've been aware both have been carrying injuries. In terms of what Jose said that's a club matter, it's not for me to comment on in terms of players playing with injuries.
"There's always a line for a player. I think players want to play, generally. In individual situations you need more information to be able to comment. It totally depends on what the injury is - what part of the body, what are the ramifications... it's a very individual thing."
England's upcoming matches are due to be Southgate's last two in interim charge of the team.