The flanker has been sidelined for nine months after suffering a neck injury against Harlequins last April.
But he has recovered sufficiently to be named in Leicester Tigers' team to face Worcester Warriors tomorrow night.
The news is a major boost to England ahead of the Six Nations and he could now play his way into Lions contention.
Croft starred for the Lions in South Africa four years ago, featuring in all three Tests and scoring two tries in the series opener.
But Leicester are wary of the need to protect the 27-year-old flanker.
"Tom is probably a week away and that is good news for us," said Cockerill speaking last month.
"It will be a slow integration and we will have to look after him. He hasn't played for eight months and we are conscious of that.
"His injury was a serious one and it's about him being confident when he comes back.
"Tom has seen the specialist and he was pretty happy with what he saw.
"He has put weight on and is looking in good shape. He is 110kg now, whereas he has always been around 104kg before.
"We feel that extra bulk will make him more robust. He actually looks like a rugby player now! It's just the healing of the bones that has to be right."