MARK Harvey says the loss of seasoned players combined with a lack of class is behind Fremantle’s inability to perform in the second half of matches.

Fremantle opened well against the more-fancied Brisbane Lions on Saturday night and led narrowly at half time in Subiaco Oval's heavy conditions before falling away to lose by 15 points.

To make matters worse for the injury-plagued club, full-back Chris Tarrant is likely to miss next week’s western derby after injuring his knee in a seemingly innocuous incident where he kicked the ground instead of the ball.

Harvey insisted there were a number of positives to be drawn from Fremantle’s performance which came in the wake of last week’s embarrassing 117-point loss to Adelaide.

"I thought it was a pretty good effort by our guys tonight," Harvey said.

"But in reality, when you have a look at the inside 50s you can see the class that we’re missing. We are lacking class and that would be in the midfield and the forward line at the moment.

"I think what we’re finding, and it’s a regular pattern, is that in most games we can be there at half time and then we fall away after half time.

"But that’s a combination of things. A lot of that’s got to do with [the fact] we haven’t got enough seasoned players at the moment."

With experienced competitors such as captain Matthew Pavlich, Aaron Sandilands and Byron Schammer out through injury, Fremantle was forced to start three first-year players in the midfield – Zac Clarke, Matthew de Boer and Stephen Hill.

Harvey said the heavy conditions had dictated a tough and physical style of play which had taken its toll on Fremantle’s youngsters.

"Tonight wasn’t a fitness game, it was a repeated effort game," he said.

"And it wasn’t a running game as such, it was a combatant game. It’s very hard to be an attacking team when you lack personnel.

"The younger players are still learning and they fall victim to fatigue quicker.

"There’ll be a big emphasis on us getting bigger and stronger at the end of the year. Right across the board a lot of our blokes need to get bigger."

Harvey said he was confident that Pavlich and Sandilands would return for next weekend’s clash with West Coast but that he would not be tempted to select young forward Chris Mayne despite a successful comeback in the WAFL reserves.