Captain Andrew Browne will miss Claremont's game against Perth at Brownes Stadium tomorrow after dislocating a shoulder against Swan Districts at Claremont Oval last Sunday.
Browne could also be a spectator for the Tigers' last home-and-away game, against East Fremantle at East Fremantle Oval tomorrow week.
But the inspirational 29-year-old is expected to be available for the second semifinal, against West Perth or East Perth, at Claremont Oval on September 8.
Football manager Dean Horsington said the club wouldn't be taking any chances with Browne, who played in the club's 2011 premiership side but missed last year's grand final win against East Fremantle with a hamstring injury.
"Andrew will miss this week but it's nothing serious," Horsington said yesterday.
"You fear the worst at first, that it's broken, but it was just dislocated and popped back in straight away.
"He had no pain afterwards and with some rehab he should be good to go.
"We are expecting him to play the last round, but either way he will definitely be fit for finals."
Horsington said Browne, who played 29 games in five injury-affected seasons for Fremantle, would do what was best for the club.
"Browney's the type of guy who will always put the team first," he said.
"If he doesn't think he is fit or can contribute then I don't think he will put himself or the team at risk."
Key Demons Matt Tedesco (knee) and Matt Moody (groin) are unlikely to be fit to line up tomorrow.
Utility player Mitch Leyendekkers is poised to earn a recall to help Christian Eyres against the league's No.1 ruck combination of Mark Seaby and Mitch Andrews.
East Perth and South Fremantle will have to find replacements for key players in tomorrow's match at Fremantle Oval.
The Royals will be without midfielder Matt Rosa, best afield in their 48-point win against Perth at Medibank Stadium last Saturday.
Rosa, who had 34 possessions against the Demons, was called into the West Coast squad for tonight's game against Collingwood at the MCG.
Rosa's Eagles teammate Ashton Hams will be missing from the Bulldogs team after being suspended at the WAFL Tribunal this week.
He received a one-week ban for striking Brennan Gillam in the Bulldogs' crushing 93-point victory over Peel at Bendigo Bank Stadium.That also ruled out any chance of Hams, the Bulldogs' best player against the Thunder with six goals and 31 possessions, being recalled by West Coast.