Greater Western Sydney co-captain Phil Davis will miss six weeks due to a back injury, further stretching the AFL cellar dwellers’ thin defensive stocks.

GWS have leaked an average of 19.8 goals this season, the worst record in the league with the exception of Melbourne.

The absence of key defender Davis, who often takes the opposition’s most dangerous forward, won’t help their chances of fixing that trend and posting a first win for 2013.

“Phil underwent scans and there was a fracture present so he’ll be on a non-weight bearing training program for the next month due to the injury,” GWS sports scientist John Quinn said of Davis, the only man to play all 22 games in the Giants’ maiden AFL campaign last year.

“We believe the injury was triggered by a knock to the lower back in recent weeks and it would continue to get worse if he played on.”

Setanta O’hAilpin, who kicked eight goals in his first two games back after a knee reconstruction, will also miss Saturday’s clash with Essendon at Etihad Stadium.

O’hAilpin (calf) is slated to return the following weekend, when GWS host Adelaide in their first game of the year at Showground Stadium.