Lewies has been out injured since March 13, but he will start for third-placed Harlequins when the welcome the Tigers to The Stoop.
The captain is one of just two changes to the Quins side that beat Montpellier last week, with fellow flanker Luke Wallace also coming in for the injured Will Evans. Harlequins beat Montpellier 33-20, but crashed out of the Champions Cup 59-60 on aggregate.
“I think Montpellier are similar to Leicester in that they’ve got a big physical pack and a good kicking game,” said No8 Alex Dombradnt.
“Our European adventure is over and it’s all eyes on the Premiership now. We can attack that knowing that’s all we’ve got. We’ll attack that against Leicester and really push on in the top four.”
There was less positive injury news for Saracens, though, as England star Maro Itoje will miss Sunday’s clash against Exeter Chiefs with a minor knee injury.
Saracens, who are sat second in the Premiership, have made eight changes to the side that beat Cardiff last week, with six of those coming in the pack as the likes of Billy Vunipola and Jamie George return to the fold.
In the back, the centres have been refreshed too with Nick Tompkins and Elliot Daly coming in for Duncan Taylor and Dom Morris.
London Irish, who are eighth in the table, are in action tonight and they must beat Newcastle Falcons to keep up their slim hopes of sneaking into the top four.
“We only have three regular league games left in the Gallagher Premiership this season, and we know that every point counts in this tight league table,” said director of rugby Declan Kidney.