Derek McInnes admits there are no guarantees Marley Watkins will be seen in an Aberdeen shirt again.

The on-loan Bristol City forward has been ruled out for up to two-and-a-half months after suffering a significant hamstring injury in a collision with Scott Brown during Sunday's William Hill Scottish Cup semi-final defeat to Celtic.

Watkins – whose Pittodrie stint expires on January 31 – is now on his way back to Ashton Gate to have his injury assessed.

McInnes would be keen to extend his loan deal but acknowledged there was a decent chance the 30-year-old former Inverness player might not be back.

"Marley is still with us now but he will go down to Bristol City tomorrow and they will assess him," explained the Dons boss.

"But there is a feeling he will need surgery – and that will be their decision once they get a second opinion based on the scan results.

"We think he will be out for the best part of eight to 10 weeks so that makes it tough for Marley to come back anytime within his loan period.

"It's not insurmountable but we obviously need to wait and see what that second opinion says.

"It's a real blow for us. I thought it would be a risky outcome because his leg sort of jack-knifed on the impact and you could see immediately he was in distress and unfortunately for us he's going to be out for a period of time.

"We've got a couple of months now to look at (extending his loan).

"I'd love to work with Marley again but there's a lot of factors involved. I think he has really enjoyed it and he's been a key player for us.

"Supporters and staff, everyone, can see the value of what Marley has brought to the team.

"I do think that playing alongside a main striker, he would cause the majority of teams a lot of problems but unfortunately it doesn't look like we're going to have the luxury of that.

"But if there was anything that could be done going forward then it would be something I'd be looking to do but he's Bristol City's player and for Marley, I think he just needs to concentrate on getting himself sorted and he doesn't need to look at anything beyond that."

McInnes will also be without Dylan McGeough and Jonny Hayes for Friday night's visit of Hibernian but the good news for the Aberdeen manager is that the groin injury which kept Hayes out of their Hampden defeat is not as bad as first feared.

"There's similarities to Dylan's injury when it first happened and while he's going to be out for quite a while, Jonny's is nowhere near as bad thankfully and he will probably be out for the next two to three weeks," he said.

"That will keep him out of Hibs and a couple of games after the international break but it could have been a lot worse so we'll take the good on that one."

The Reds are looking to move up to joint second with a victory over Jack Ross' team.

"A win tomorrow will be our second strongest start in the last 20 years I believe," added McInnes.

"We feel we've made a positive start but winning tomorrow would reinforce that."