The Waratahs have suffered a blow ahead of the Super Rugby season as playmaker Berrick Barnes looks set to miss the opening rounds of Super Rugby due to injury.

Barnes injured his knee in a Waratahs training session on Tuesday with Sydney University and has already been ruled out of the franchise's final trial match against the Crusaders at Allianz Stadium next week.

Waratahs coach Coach Michael Cheika initially said that he hoped Barnes would be ready for their Super Rugby season opener against the Reds on February the 23rd.

However backs coach Daryl Gibson has revealed that Barnes has strained his posterior cruciate ligament and would likely miss "the first few rounds".

Barnes had looked good in training prior to the injury and on Monday said that he was looking for a strong season with the Waratahs - possibly at No. 10 or No. 12.

"Berrick can play a number of positions and has shown that he's very adept at a number and so he's obviously a candidate for that fly-half position," Gibson told WAToday.

"It's unfortunate he's sustained that knee injury, he'll be unlikely to be involved in the first few rounds."

Coach Cheika now says that the injury is a blow for Barnes as he will fall behind the rest of the squad as they will all have had some game time.

Barnes' absence also looks like it will benefit Bernard Foley and Waratahs new recruit Ben Volavola who was a star for Southern Districts in their campaign in the Shute Shield last year.

"It's going to put (Barnes) a bit behind the eight-ball because all the other lads will have had a practice match and put their hands up for a spot," Cheika said.

"Berrick still hasn't learnt the fact that he's a distributor and he's got to pass the ball and not run into 10 forwards at once, which he chose to do for some reason.

"It's part of him you like as a player because he's a tough guy and he wants to do as much as he possibly can, so you can't complain about it when he actually does it. "

"In a game, you want him to be that type of character, it's his personality to get stuck in there."

The Waratahs final trial is against the Crusaders next week and former Crusaders assistant coach Gibson is now Waratahs backs coach is expecting a tough trial in Sydney for his new side.

"I would definitely look for the Crusaders to spread the ball and really use the width of the field," he said.