WEST Coast midfielder Chris Masten says coach John Worsfold faces some selection headaches this week, admitting that his spot in the team isn't safe ahead of Saturday's preliminary final clash with Geelong at the MCG.

The Eagles are at close to full strength as they prepare to play off for a spot in the Grand Final, with only midfielder Matt Rosa potentially unavailable after six weeks on the sidelines with a knee injury.

Masten has played five straight matches, including a brilliant 31-possession, three-goal performance against the Brisbane Lions in round 23 that seemingly secured his spot for the finals.   

However, the 22-year-old's form tapered off against Carlton last Saturday night and he was substituted out of the memorable three-point win during the last quarter. 

"I don't think I ever feel really safe," Masten said this week.

"It's amazing competition. We've got pretty much a full list to choose from, so the coaches might have a bit of a headache, which is good for the side.

"Obviously you have to be playing pretty good to keep your spot. I've been reasonably happy with how it's gone, but there's lots of competition.

"The coaches are probably having a really hard time selecting the team. You can't rest on your laurels."

Masten has played 53 games in an injury-riddled four-years and he said it meant a lot to him to work his way back into the team and play in two finals so far this season.  

The former No.3 NAB AFL Draft pick said the groin, knee and ankle injuries he had endured had dented his confidence, but he had rediscovered some belief with his standout performance against the Lions at the Gabba four weeks ago.

"I've worked so hard trying to get back into the side, and to play in a couple of finals and win one, it makes me really happy," he said. "Hopefully I can hold my spot and we can keep winning.

"Once you lose confidence it's hard to get it back, so I'm glad I got it back a couple of weeks ago. Hopefully I'll stay in the side."

Competition for spots this week is most likely to come from Brad Ebert, who has played 22 matches this season, including the qualifying final loss to Collingwood at the MCG.

The versatile 21-year-old has offered a marking presence across half-forward and could provide an extra strong body in the midfield rotation against the Cats.

Rosa, who was an emergency for the Eagles' 2006 premiership, last played in round 20 against Richmond, but teammate Adam Selwood said the much-improved midfielder had not been ruled out this week. 

"He's been doing a lot of running work and his touch was really good," Selwood said.

"He's been out for five or six weeks but he's been around a situation in '05 when we had a lot of injuries [in the finals] and players went out.

"Kasey Green [was recalled for the grand final], Travis Gaspar [was recalled for the preliminary final] and I think Damien Adkins nearly got a grand final berth after not playing a month of footy.

"So Rosa understands that, and even if there aren't any injuries he could very well come into the side this week."

Nathan Schmook covers West Coast news for afl.com.au. Follow him on Twitter: @AFL_NSchmook