Plymouth midfielder Jamie Lowry has injured an ankle in training and Argyle are assessing how long he will be out of action.
The 25-year-old hurt the same ankle in pre-season, ruling him out of the first two months of the Pilgrims' season.
"Jamie went over on his ankle in training last week. I'm hoping that's not too serious," manager John Sheridan told the Western Morning News.
"I think it's the same ankle he did during the summer, but not as bad. He has caught it and it's swollen."
Meanwhile, Sheridan admitted he is unsure when defender Curtis Nelson will return to action having missed the last six games because of a groin problem.