Anxious wait on fitness of injured Bent, Bennett and Lichaj
Bent missed out against Sunderland after picking up an ankle knock in training on Friday.
Bennett hobbled off at the Stadium of Light after opening up the wound in his knee that was sustained at White Hart Lane.
Lambert will now check their fitness through the week as the team prepares for the arrival of the Red Devils at Villa Park.
Lambert said: "I think Darren has hurt his ankle - the same ankle he injured against Wigan.
"We couldn't take a chance with him against Sunderland.
"Darren wasn't fit and was really hobbling at Bodymoor Heath on Friday after training so we couldn't bring him up with us.
"Is it serious? I don't know yet. He will get treatment on it during the week and we will see.
"I know it was serious last year when Darren hurt the ankle and he has kind of hurt it a little bit.
"Joe's wound keeps opening up at the moment so we will have to try to patch the both of them up.
"Obviously we already have a few of the lads at the back out already so hopefully we will get them back as quickly as possible."
Bennett's first-half replacement on Saturday, Eric Lichaj, was also withdrawn after the break after picking up a groin strain.
Lichaj is suspended for the Red Devils game on Saturday but, nevertheless, Lambert will hope to see him recover as soon as possible.
Make sure you're here to roar on the lads against Manchester United.