Benteke has ruptured his Achilles tendon and will need surgery on the injury, ruling him out for six months and meaning he may not play again until October at the earliest.
However, even though Bent is due back at Villa Park from his loan spell at Fulham this summer, he won't be considered by Lambert.
Asked if the former England man could be brought back into the fold, the Villa boss said: "No, the club's moved on.
"Darren has not really played for me for two years. Obviously he's been on loan at Fulham, here we've had Christian's form and that's football. Whatever happens at the end of the season will happen."
Lambert confirmed that Fulham do not have an option to buy Bent written into the deal once his loan expires.
"No, he comes back. If they want to buy Darren it's an avenue they can go through, so we'll just wait and see," he added.
Bent looks unlikely to make his move to Fulham permanent given he has failed to find any real form with just six goals from 28 games.
He clashed with manager Felix Magath at the weekend after he was left out of their lost to Everton.
But the German insists that he and Bent have settled their differences.
"Darren came to me on Tuesday and we talked together. It's fine for me," he said, insisting the forward was only left out of the Everton game because of an injury he suffered the day before.
"It's normal you have discussion about such things. He stopped training on Friday," Magath added.
"He left the pitch to go to the medical staff and he didn't train. On Saturday he was better and he told me 'I'm fine' so I decided to take him on the bench. He is a player we need.
"The risk was to let him play was too high because he cancelled the training on Friday."