Manager Neil Lennon has also revealed that he is hopeful of potentially having the 20-year-old back available for selection before Christmas.

The on-loan Dundee United centre back was substituted inside the final 10 minutes of Saturday's home draw with Livingston.

That led him to miss Tuesday's game with Partick Thistle - the first Championship fixture he'd not featured in this season, and only the second in all competitions - after which Lennon said he'd be "out for a considerable period of time".

Cleall-Harding, who represented Scotland under-21s during the recent international break, had a scan and is set to see a specialist tomorrow (Friday) to determine whether he needs an operation.

The Pars are keeping their fingers crossed that won't be the case, but are facing up to being without the defender for a number of weeks.

"We're still waiting to see if he's going to need surgery," Lennon said.

"But we're hoping that's going to be avoidable. There is damage in there, but I don't think there's a rupture.

Dunfermline are hopeful Sam Cleall-Harding won't need surgery on a hamstring injury. (Image: Craig Brown.)

"So, from what we gather, he may not require the surgery, but we're going for a precautionary view more than anything else.

"But he's still going to be out for a concerted period of time.

“He's been brilliant, he’s absolutely outstanding. We're delighted with bringing him in. We're delighted with his contributions up until now.

"Hopefully we'll have him back before Christmas.

"Part and parcel of the game, unfortunately, is injuries and it’s come out of the blue, really, because he's been looking great.

“He’s just off the back of playing for Scotland (under-21s) as well, but his form for us was outstanding, so it’s a big blow to lose him.

"But Aaron (Donnelly) has come in and done exceptionally well himself. He played very well on Tuesday, so we’re very pleased with him as well."

Donnelly replaced Cleall-Harding against Livi, his first minutes since mid-August, which was also his last starting berth prior to playing against the Jags midweek.

The 23-year-old Northern Ireland cap has had to be patient since singing on loan from Dundee, particularly after Lennon elected to make a formation switch, from a three-man defence to a back four.

The Pars boss admitted that, and the team's levels of performance, had impacted Donnelly's game time, continuing: "Nuru (Nurudeen Abdulai) and Sam were outstanding.

"It’s a bit like Charlie (Gilmour) at the minute, with the way Fonzie's (Alfons Amade) been playing. It's difficult to get in when players are playing so well.

Aaron Donnelly replaced Cleall-Harding in defence. (Image: Craig Brown.)

"So, like Aaron has said, you just have to be patient, and we say this to all the squad - there are going to be opportunities coming along.

"It's not about coming in and taking the chance. It's about coming in and just being the player that we know that you can be, so, Aaron's done that, and he's played very well.

"We've got cover there with John Tod, who can play both sides as well.

"So, I’m pleased with Aaron."

Heading into Saturday's match with Queen's Park, Lennon reported a largely clean bill of health, confirming that Chris Kane is fit and in contention to be part of the squad.

He added that Freddie Turley, yet to play since returning to the club on loan from Derby County, is now "getting on the grass", and is likely to be available to feature in the coming weeks.