WEST Coast's season could hinge on the fate of star ruckman Nic Naitanui's anterior cruciate ligament as the Eagles fear the worst but hope for the best following his left knee injury against Hawthorn.

The Hawks are also hoping for the best and fearing the worst for their ruckman Jonathon Ceglar after he suffered a right knee injury only minutes earlier in the third quarter of Friday's clash at Domain Stadium.

Ceglar was the third man up in a marking contest when he collided with Eagles forward Jack Darling.

Ceglar grabbed at his right knee and the stretcher was called on to the ground, but he hobbled off in the arms of trainers.

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Minutes later, with the Eagles leading by 35 points, Naitanui came down awkwardly on his knee after going for a mark against Hawks skipper Luke Hodge.

Eagles medical staff conducted a mobility test on Naitanui's knee on the bench.

Naitanui's importance to the Eagles cannot be understated after he kicked a sensational match-winning goal against Greater Western Sydney in a thrilling one-point win last week.

The injury left coach Adam Simpson very downcast following the Eagles' best win of the year. 

"Fear for the worst, hope for the best at the moment," Simpson said post-match.

"It's too hard to tell. It doesn't look great, but we'll find out in the next few days.

"It's a little bit indifferent, the mood. We're really proud of our performance as a collective and you know we have been written off for a fair bit of the year, but I thought tonight we stood pretty tall against a quality opposition.

"Then your mind slips to Nic's situation and you think about the worst, which we shouldn't do. But it's a bittersweet feeling at the moment."

The mood was exactly the same in the Hawks' camp given the importance of Ceglar to their premiership hopes.

"It was a classic mechanism for an ACL," Hawthorn coach Alastair Clarkson said.

"We're half-suspecting that will be the case, but we just hope for the best that it's not. We'll know that once we get it confirmed by scan."  

Simpson said the Eagles would need to be mature enough to play well without Naitanui if he is ruled out for the rest of the year.

"He's one of our best players, and we saw the influence he’s had in the past few weeks," Simpson said.

"But we need to mature to a point where we don't have to rely on just one player to get it done. It's another test for us, which our boys are looking forward to."

Clarkson admitted he was thin for ruck options to replace Ceglar but vowed the Hawks would find a way as they have done all season.