Lewis suffered his injury in the opening seconds of the third term at the MCG on Saturday, when he collided with teammate Matt Spangher in a marking contest.
Lewis left the ground briefly for treatment and was substituted from the game late in the third term.
"From what I can gather, he's copped a pretty severe corky in that marking contest early in the third quarter and then soldiered on manfully for the next 20 minutes or so until three-quarter time," Clarkson said after the Hawks' three-point win.
"It's always around about that time that you're considering making your sub anyway and he was just starting to labour a bit towards the end of the third quarter, so we thought it best to get (Jonathan) Simpkin on.
"As for his recovery, I'd be staggered if a warrior like him doesn't get himself up, but stranger things have happened.
"But we'll have to monitor that bleed over the next couple of days and see how it progresses.”
Clarkson said it was unlikely the Hawks would make "significant" changes to their team for the Grand Final against the Sydney Swans, and was tight-lipped about star forward Cyril Rioli's chances of a recall.
Rioli has not played since the Hawks' round 15 win over Gold Coast, when he suffered a severe hamstring tendon injury.
The two-time premiership Hawk is set to return to the field on Sunday, for the Box Hill Hawks in the VFL Grand Final against Footscray.
Asked whether there was an easy answer on what Rioli had to do to earn a senior recall next Saturday, Clarkson said there was not.
"He hasn't played for a long, long period of time so we went through a tough process throughout the course of this week in terms of working out which game he'd play in, whether it was going to be in the senior side for Hawthorn or at Box Hill," Clarkson said.
"In our wisdom, we thought having missed so much footy, he's better off just trying to get some game time at Box Hill and we'll just see how he recovers from that.
"If he plays well and his body is fine, he'll be in consideration for selection next week.
"But a lot of things have to go right over the next couple of days for that to happen."
