St Kilda defender Sam Gilbert faces a delayed start to the AFL season after sustaining a foot injury in pre-season training.

Gilbert was diagnosed with a stress fracture on his left foot and had surgery to insert a screw on his metatarsal bone on Monday.

The club has been told to expect a six-week recovery, putting Gilbert in doubt for the Saints’ round one clash with Melbourne on March 21.

St Kilda’s football head Chris Pelchen said he felt for Gilbert, who missed 13 matches last year with a knee injury.

“It’s disappointing for Sam, particularly because he has had a solid pre-season to date,” Pelchen said.

Gilbert will miss St Kilda’s pre-season fixtures, which begin on February 19 against Western Bulldogs.