FREMANTLE ruckman Robert Warnock will miss the rest of the season, having succumbed to a shoulder injury.

The 21-year-old was left out of Fremantle's side to take on the West Coast Eagles in this weekend's Western Derby and will undergo surgery on Friday.

The club is hopeful the timing will allow Warnock to recover for the pre-season and will also make a point of retaining the talented big man's services in the coming weeks.

Incoming Fremantle CEO Steve Rosich, in accepting his own appointment last week, highlighted Warnock's importance.

"Rob Warnock is a required player," he said. "He is a young and talented player, and we are working through a process at the moment to hopefully see him stay here, but we aren’t in a position to announce anything."

Warnock has played nine games for Fremantle in 2008 after 12 in his debut season.

He joined Fremantle via selection 42 in the 2005 NAB AFL Draft and his brother, Matthew, is a defender for Melbourne.