FREMANTLE'S key-position injury crisis has deepened with forward/ruck Rory Lobb undergoing season-ending shoulder surgery.

The 26-year-old was put under the knife on Monday and joins Jesse Hogan (foot), Matt Taberner (foot) and Alex Pearce (ankle) in being sidelined for the rest of 2019.  

FULL INJURY LIST Who's ruled out and who's a test?

After first injuring his shoulder in the dying stages of the one-point win over Sydney in round 18, Lobb then fronted up against the Western Bulldogs a week later.  

Lobb in action against the Western Bulldogs in round 19. Picture: AFL Photos

However, on further assessment the Dockers have decided to take the cautious approach with Lobb to have him ready for the start of 2020 pre-season.  

"Rory principally had a shoulder injury, but in fact it's an anchor for one of the muscles of the upper body that comes off the front of the chest," high performance manager Jason Weber said. 

"He damaged that bone a couple of weeks ago, he was able to play through but unfortunately, the damage has required surgery.

"He's had that done and he's now looking forward to a strong rehab period." 

The Dockers haven't ruled out defender Nathan Wilson for this week's clash with St Kilda as he continues to manage a toe injury that forced him out of last week's win over Geelong.

"Nathan injured his toe some weeks ago and he was able to play through for some time," Weber said. 

"At this stage he's still working through with the doctors on his capability of possibly getting up for this week or in the near future." 

Defender Luke Ryan (hamstring) is a fortnight away from returning with Brennan Cox (hip) to miss at least one more match.