ALL AUSTRALIAN defender Luke McPharlin will miss up to five weeks with a torn calf. 

The Fremantle veteran spent the last quarter of Sunday's 30-point win over St Kilda on the bench with ice on his left calf and was already expected to miss this week's derby clash with West Coast. 

However, coach Ross Lyon told radio station 6PR that scans had revealed a significant calf tear that would force the star backman out for five weeks. 

Lyon remained confident his side could cope with yet another senior player's prolonged absence through injury. 

"At the end of the day, we've been able to cover for our losses. It's a big loss, but we certainly need Alex Silvagni and Peter Faulks to step up in that role," he said. 

"The positive is he will be back, but it's a significant calf injury and there's some adversity there for the group to overcome."

It is a major blow for Fremantle, which sits fifth on the AFL ladder with eight rounds to go. 

McPharlin played 21 of the 22 home and away rounds in 2012, but missed the club's two finals with a hamstring injury. 

The Dockers lost two of the three matches the 31-year-old did not play. 

Both were against Adelaide at AAMI Stadium, in round 20 when he was suspended, and in a semi-final. 

The Dockers did beat Geelong in an elimination final at the MCG without McPharlin.

Alex Silvagni looms as the most likely candidate to tackle the Eagles' Coleman Medal leader Josh Kennedy in the derby.
 
"Alex came in and played on (James) Podsiadly in a final last year so we know our pressure is good enough and we trust Alex to do the role," Lyon said in the post-match press conference on Sunday.