Striker Bent missed England's midweek draw with Montenegro after he picked up a groin injury in training with the national team.
It is the third time that the former Tottenham and Charlton man has been injured while with Fabio Capello's side, and his club boss is at a loss to understand why.
"Your worst fear is getting the call saying he is injured. It is a shame for Darren because that is three times he has been with England and got injured," said Bruce.
"If you have a problem with a player, someone who has a bad back for example, you have dialogue with the England medical staff but you can't interfere with training games.
"I will be informing my medical department to have a word. If it happens once, fine.
"But if it has happened so often when he has been away with England then that is not healthy, especially as he has not even missed a training session since he has been here."