ADELAIDE football operations manager Phil Harper has played down speculation over Scott Stevens' playing future as the utility battles to overcome the after-effects of another concussion.

Stevens copped a knock to his head at training following the Crows' loss to Fremantle in round three.

The 29-year-old passed a concussion test that afternoon, but developed migraines and nausea the next day.

He was able to complete the club's main training session last Thursday, but ruled himself out of the game against Port Adelaide when his condition worsened.

It was the fourth documented concussion Stevens had suffered in the past two years.

He missed three games after being concussed against Fremantle in round one last season and sat out Adelaide's clash with Geelong in round four, 2009 for the same reason.

He also missed the club's NAB Challenge game against Freo at Thebarton Oval in March this year after copping another knock at training.

Concerned by the frequency and severity of Stevens' concussions, the Crows medical staff referred him to a specialist.

Harper said the specialist had conducted tests which suggested the former Sydney Swans forward had not sustained long-term damage from the repeat concussions.

"We sent Scott off to the specialist, who he's been to before, and he did a whole series of tests on Scott," Harper told afc.com.au.

"The specialist suggests it [the concussion] isn't having long-term effects and that's why the tests were done. Scott's no worse off today than he was a couple of years ago when he got a big knock.

"Is it a concern? Yes, any head knock to Scott Stevens will always be a concern for us, but the specialist is saying there's nothing to be alarmed about."

More concerns over Stevens' condition were raised when he failed to complete training at Max Basheer Reserve on Tuesday.

However, physical performance manager Stephen Schwerdt said the plan was always for Stevens to leave the track after the warm-up.

"Scott will try and train tomorrow and Thursday," Schwerdt said.

"He's feeling okay at the moment and all being well will be available to play this weekend."

Concussion has been a topic of debate in recent months following claims by ex-Melbourne defender Daniel Bell that multiple concussions sustained during his playing career had left him with permanent brain damage.

Ex-Fremantle utility Daniel Gilmore went one step further, claiming his former club's negligence contributed to a career-ending head injury.

At the start of the season, the AFL revised its concussion guidelines to prevent a player diagnosed with concussion during a game from returning to the ground.

Harper said the club would continue to take a cautious approach with Stevens' recovery.

"If it was someone else we probably wouldn't be as cautious," he said.

"We have a huge amount of trust in Scott. If he trained fully on Thursday we'd probably be prepared to pick him, but we'd be very reliant on what he tells us.

"He's become a good judge on this [concussion] and we know he wouldn't say he was right if it wasn't."

Katrina Gill covers Adelaide news for afl.com.au. Follow her on Twitter: @AFL_KatrinaGill