The reigning IAAF female world athlete of the year incurred the injury during the final of the Gippsland Gift at Traralgon.
Pearson's coach Sharon Hannan said it appeared to be a "mild strain" with no visible tear of the muscle.
"Sally's had some treatment in Melbourne today and she's going to stay tomorrow as well and see the Athletics Australia head medico Adam Castricum," Hannan said.
"She'd trained off the planet last week, putting in the most amazing week I've ever seen her put in anywhere around this time of the year.
"There had been a tiny bit of tightness in her quad but nothing
we were too concerned about."
Pearson had planned to contest several events at the Gippsland Gift meeting which would have replicated the heavy workload she regularly did during a Saturday training session.
She suffered the injury midway through the 120m final.
"By all accounts Sally was going to be an extremely clear winner," said Hannan. "But she felt it with about 50m to go and had to ease down."
Pearson, 25, underwent an MRI scan on Monday and is likely to go straight into a rehab program.
She and Hannan are hopeful she will be back to full fitness in time for the Brisbane Track Classic on January 14.
Pearson is the short-priced favourite to win gold in the 100m hurdles at the London Olympics after an all-conquering 2011 season.
She moved to fourth on the alltime list with her winning time of 12.28 seconds in the world championships final in Daegu, South Korea.
The Queenslander was on track for an unbeaten year in her pet event before crashing into a barrier in the final Diamond League meet in Brussels.
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