All four players have been forced out of the Wembley international because of injury.
Liverpool skipper Gerrard has a broken toe and played against Chelsea in the Premier League on Sunday with a pain-killing injection.
After the game, Gerrard admitted he was unlikely to face the Germans as he needs to rest the injury. He was set to have an
Hargreaves complained of knee problems following Manchester United's derby defeat at City, with Sir Alex Ferguson suggesting the midfielder would not be joining up with the England squad.
Tottenham striker Bent has been forced to withdraw from the squad after picking up a thigh problem in Saturday's 4-0 home win over Derby.
The trio join Campbell in pulling out of the squad after the Portsmouth defender had already been ruled out over the weekend because of a groin injury.
Hargreaves and Campbell were required to report to the team hotel. However, after they were assessed by the England medical staff, it was decided their respective problems were significant enough to rule them out of contention.
One plus point for England boss Steve McClaren was the attendance of former England captain David Beckham at the training session at London Colney.
The LA Galaxy midfielder had only just returned to England from the United States, but showed little sign of jetlag as he joined in training with other players.
The 32-year-old delighted several fans who had won a competition to attend the open session and also took some time out to chat with Arsenal boss Arsene Wenger.
As well as the three goalkeepers, there were 13 outfield players of the remaining squad who took part in training, including strikers Peter Crouch and Michael Owen, as well as Chelsea midfielder Joe Cole.
However, the remaining players who were in action with their clubs on Sunday did not take part outside and instead underwent a recovery session as expected.
Doubts had been raised as to whether Beckham could cope with the demanding schedule of jetting back across the Atlantic.
However, McClaren had every confidence the former England captain could take everything in his stride.
He explained: "I think David can combine playing out there and coming here.
"I understand everyone's concern about that - but the proof will be not just in his performances but also in training.
"When we brought him back (last time) in the Monday training session, there was a lot of pressure on him and a lot of people looking.
"His performance in training got rid of the doubts.
"We will know that. That is what we assess. It is not just in games we look at him, it is in training as well."