Aberdeen boss Derek McInnes today admitted he fears Zak Vyner’s season could be over after suffering a shoulder injury.

And as the Dons’ injury crisis deepened McInnes is ready to take in “two or three” January signings as reinforcements.

On-loan Bristol City defender Vyner was forced off in the 1-1 draw at Hearts having suffered an injury to his right shoulder. Vyner was ruled out for three weeks last month with a similar injury to the same shoulder sustained in a training ground collision.

The 22-year-old is set to see a specialist and McInnes fears the prognosis will be surgery is needed, which will end his season.

It would be a further blow as Greg Leigh and Craig Bryson were both recently ruled out for two months.

McInnes said: “Zak has done his shoulder for the second time so obviously there is a concern there.

“The last time Zak was out for three weeks and the specialist said he didn’t need the operation.

“There will be a revisit to the specialist and between ourselves and Bristol City we will make a decision on what is best for Zak.

“I think there is a real risk he will maybe need the operation that was maybe suggested prior.

“There will be a visit to the specialist and between ourselves and Bristol City we will make a decision on what is best for Zak.

“I think there is a real risk he will maybe need the operation.

“That would mean Zak would be out for the season.”

Vyner walked off at Tynecastle with his right arm in a sling in what was the third injury blow in recent weeks.

It was recently confirmed on-loan NAC Breda defender Leigh is out for eight weeks after suffering a fractured tibia.

Summer signing Bryson is also set to undergo surgery on an ankle injury this week and will be sidelined until late February.

On top of this, attacker Scott Wright is out for the season with a cruciate ligament injury and defender Andy Considine failed a fitness test on the day of the Hearts game on a hip problem.

McInnes said: “We are already without Greg Leigh for two months with a stress fracture and Craig Bryson goes in for his operation in the next couple of days. Bryson is out for two months, so we have been without some key players.

“Hopefully if that is the case we can do some smart work in January and bring two or three additions in.”

Aberdeen have St Johnstone winger Matty Kennedy on their radar.

Kennedy is out of contract in the summer and free to talk to interested clubs from the opening of the transfer window.

Sunderland’s Dylan McGeouch remains a potential target.

McInnes was left frustrated as his side failed to capitalise on a man advantage after Hearts were reduced to 10 men mid way through the second half when Sean Clare pulled back Jon Gallagher.

From the subsequent free-kick substitute Niall McGinn, on for the injured Vyner, netted in off the post.

McInnes said: “On the balance of play we deserved our point but certainly no more than that.

“I thought Hearts controlled the middle of the park and moved the ball well in the first half without really hurting us.

“I was desperate to get to half-time to make one or two little changes.

“I thought we were better in the second half as Hearts did not have it all their own way.

“However, they did score a brilliant goal which was the story of the game.

“Hearts scored a brilliant goal then Niall McGinn did the same for us. Once we got the goal and the initiative after Hearts went down to 10 men we got ourselves into some good areas to maybe get ourselves the second goal.

“Hearts were maybe on the ropes then but they galvanised themselves and showed a bit more composure in the last 10 minutes. More than my team.”

McInnes opted to go with two strikers as he paired Curtis Main with Bruce Anderson, who was handed a first start of the season.

Leading scorer Sam Cosgrove was suspended.

McInnes said: “I felt I had to get two strikers on the pitch as I was keen to play young Bruce Anderson and went with two with Curtis Main up alongside him.

“When you try to put two strikers together that has to be really effective for you because there is a trade off elsewhere.”