St Kilda are optimistic spearhead Nick Riewoldt will play again this season but doubt the superstar will be fit for Friday night's must-win clash against Geelong.
Riewoldt was subbed off at quarter time during the Saints' 25-point win over Melbourne after his knee hyper-extended as he dived to take a contested mark on the lead 16 minutes into the first term.
The 29-year-old immediately went for scans and was cleared of ligament damage.
But there is still a concern that a split tendon behind his right knee may end his season.
"I didn't look great. The first thing that goes through your mind initially is an ACL. We will assess him through the week and see where he sits," coach Scott Watters told reporters after the match.
"When you see a foot slide and the ground shift you straight away think the worst. (But) in the scheme of things it's pretty minor compared to what it could have been.
"At this stage, that's the early diagnosis, but with these things you get a scan, you let things settle. What I say here now may change in 24 hours but initial reports are very optimistic that he will play again this year."
The Saints booted the match's opening four goals against the Demons and appeared destined for a dominate win.
But the standard fell away dramatically when Riewoldt was carried off.
Watters conceded the Saints may have lost focus after seeing their skipper unable to walk and in such a despairing mood.
"Players know when the captain goes off. Players are emotionally linked to their team-mates. Did it distract them for a small period? Perhaps," he said.
Sloppy ball use was again a problem for the Saints, who moved to within four points of the top eight with three matches left.
"Our ball use is going to be a continual focus for us. All sides need to be skilful and look after the ball," Watters said.
"The amount of turnovers between the arcs in the first two quarters didn't really enable both sides to consolidate their defence.
"Once we tidied up our ball use, which I think was the main difference in the third quarter, we were offensively more effective and it put us in a much better position to defend."
Watters was pleased that young players including defenders Jarryn Geary and Tom Simpkin and in particular midfielder Jack Steven were now playing vital roles for the Saints.
Steven, who finished with 24 disposals and eight clearances, was the driving force behind St Kilda's third-quarter purple patch where they added seven goals to two to set up a 50-point lead at the last change.
"He took a really big jump forward again today. He played the sort of footy we saw from him earlier in the year which is great," Watters said.