HAWTHORN's premiership defence has suffered another significant blow with reigning best and fairest winner Josh Gibson set to miss about 10 weeks with a ruptured left pectoral tendon.
Hawks football manager Chris Fagan told the club's website earlier this week that Gibson had suffered "a bit of a stinger" in his left shoulder in a marking contest in last Friday night's loss to the Sydney Swans.
But the Hawks announced on Thursday afternoon that Gibson had experienced continued discomfort after the game with scans on Wednesday revealing "a pectoral major tendon rupture".
Gibson was set to undergo surgery on Thursday afternoon to reattach the pectoral tendon to the bone.
Fagan said the Hawks' initial diagnosis had been based on testing that showed Gibson still had full strength and movement in his left shoulder.
"This is obviously very disappointing for Josh, but he's a player of great character and will approach his rehabilitation with the highest level of professionalism to ensure he can have an impact in the back end of the season," Fagan said.
The Hawks' announcement came less than two hours after the Western Bulldogs confirmed that their forward Tory Dickson would miss eight to 10 weeks after rupturing his left pectoral muscle against Melbourne last Saturday night.
Melbourne key defender James Frawley missed three months after pectoral surgery in 2011, but took some time after his return to get back to his best.
Gibson's setback continues the Hawks' horror run with injury that has recently sidelined Sam Mitchell (hamstring), Cyril Rioli (hamstring), Brian Lake (calf), Jed Anderson (shoulder) and forward Brendan Whitecross (knee) for extended periods.