Dickson will consult with a surgeon on Tuesday and is understood to be facing an extended spell on the sidelines, judging from a similar injury suffered by Melbourne's James Frawley three years ago.
Frawley had surgery after tearing his pectoralis muscle during a gym session in January 2011.
Although the Demon returned in round two – some three months later – he didn't rediscover his best form for weeks.
The Bulldogs' medical services manager Andrew McKenzie told the club's website that Dickson's pectoral muscle needed attention.
"Tory has ruptured his pec muscle, that will need a repair so he’s going in to see the surgeon tomorrow," he said.
The injury is a cruel blow for Dickson, who was subbed out during the second quarter on Saturday night.
The 26-year-old – who re-signed with the Dogs for two more years last week - showed promising signs by booting three goals in round six against Adelaide, his first AFL game since round one.
"Tom tightened up in his calf in the second quarter and he was taken off to be assessed by the doctor," McKenzie said.
"He looked reasonable when he was assessed, so we were able to strap him up to support the area and he managed to play out the game.
"Tom’s calf is still tight but it hasn’t aggravated any further and he came into recovery yesterday and he felt reasonably good.
"We are getting some scans on him this afternoon to see what has happened."
In other news, athletic tall Jarrad Grant made a successful return from a fractured foot in the VFL, although defender Matt Fuller suffered a minor shoulder issue which will be monitored this week.
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