The 27-year-old, who was making only his second start since returning from eight months on the sidelines after a shoulder operation, suffered a back injury but Tigers director of rugby Richard Cockerill said it was not serious.
"Crofty just got a knee in his back and it was a bit bruised and a bit tight in the soft bit between his hip and spine," Cockerill said. "It was just bad luck, one of those things. He needed to play but that's life. It's nothing serious, just a bang."
Croft's team-mate Tom Price was taken to hospital after being carried off on a stretcher with a neck injury on his debut. The 19-year-old was knocked unconscious in the 30th minute at a ruck and had to be treated for 10 minutes on the field.
Cockerill said: "He is at the hospital. He is not very good. It was his neck. He was unconscious and struggling. He has got movement in his hands and feet and, hopefully, he will be okay.
"He is over at the hospital being dealt with, so it's not ideal for a young guy who was meant to be playing for England Under-20s next week."
Leicester started the day bottom of Group B, but the five points secured in today's five-try drubbing of Wasps put them on nine and kept alive their hopes of holding onto their title.
They visit Llanelli Scarlets in their final pool match next week, but Cockerill made it clear that the Aviva Premiership game against London Welsh in a fortnight was his priority.
He said: "After last week's Heineken Cup win over Toulouse, it was tough. The atmosphere is never quite the same. But it was a good result for us and some guys got a run-out. We go to Scarlets next week with half a chance of qualifying for the semi-finals.
"I understand Sale won but I don't know where they go next week. I still can't work out how the pools work! For us it's about London Welsh in two weeks' time. That's the important game."
- Sports & Recreation
- Richard Cockerill