The striker was brought off after 28 minutes and replaced by Libor Kozak who scored the only goal of the afternoon on the half-hour.
Brad Guzan also saved a penalty as Norwich slipped to a second consecutive but the main talking point was the injury to Villa talisman Benteke.
"I think he's not too bad," Lambert told BT Sport. "I think he's actually slipped, I think that was the initial injury but we'll see how he is.
"I was delighted for Kozak to come on and score his first goal and that's why we brought Libor here, we needed some back up just in case Christian got injured."
It was far from a classic encounter at Carrow Road but Lambert was delighted to come away from his former club with three points.
"We came here with a lot of injuries and a lot of lads had knocks which we had to play down but credit to every one of them I thought they were outstanding.
"I thought the penalty when Guzan makes the save was a massive turning point and after that we could have been two up early on so (I'm) delighted with the lads' performance.
"I'm delighted. I thought coming here was always going to be a difficult game. Norwich make it really hard.
"On the counter attack I think we were excellent and to be fair the back four and (Fabian) Delph and the other lad in front of them, I thought they were terrific."