ST KILDA midfielder Koby Stevens faces an indefinite stint on the sidelines as he deals with delayed onset concussion.
On a positive note, the Saints are optimistic Tim Membrey has overcome his right knee injury and will be fit to face Greater Western Sydney on Saturday afternoon at Etihad Stadium.
Stevens suffered a head knock in round one against Brisbane, when he was one of his side's best after restricting star Lion Dayne Zorko to 14 disposals.
However, he didn't report anything that would spark fears of concussion and played the following week, before being dropped for round three and not playing any football that weekend as the senior side's carryover emergency.
Leading up to the round four clash against Geelong, Stevens experienced concussion-related symptoms.
The 26-year-old therefore didn't play at any level over the past weekend. He took to the track very briefly last Thursday at the main training session and was restricted to running laps.
St Kilda football manager Simon Lethlean expects the tough nut to miss several weeks at the very least.
"As is normal practice, Koby won't return to training until the symptoms have subsided and he's given the all clear from our doctors," Lethlean told saints.com.au.
"While we can't put a timeframe on that, he'll continue to work closely with our conditioning and medical teams over the next few weeks and complete the necessary tests."
It's an untimely blow for the 1-3 Saints, as they face a tough month while looking to rectify their flagging season.
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Defender Dylan Roberton, who made the Virgin Australia All Australian squad of 40 last year, is expected to miss the next fortnight and possibly longer as he deals with a heart issue after he collapsed against the Cats.
St Kilda head physiotherapist Andrew Wallis told saints.com.au Membrey looked set to return, while the club is hopeful Jimmy Webster will be back as well.
"Tim Membrey trained fully today, so as long as he gets through training on Thursday, he'll be back in," Wallis said.
"Jimmy Webster similar. He trained today. We need him to get through on Thursday with his hip flexor.
"Certainly if he doesn't get through this week, he'll be well ahead of the curve to play next week."
Promising big man Rowan Marshall will have further testing for concussion and is in doubt to face the Giants.
In good news for Nathan Freeman, he has recovered sufficiently from right hamstring surgery to rejoin the main group.
"He full trained today for the first time and he will full train on Thursday. He's only two weeks away," Wallis said.
