Peterborough United defender Ryan Bennett is set to undergo tests on the knee injury he sustained on Saturday.
The 20-year-old was substituted after picking up a knock in the 5-2 win against Oldham Athletic.
Boss Gary Johnson told BBC Radio Cambridgeshire: "It was a lateral ligament that was sore.
"The medical team said if he plays on he'll be out a lot longer. Gabby's been doing very well in training and I had no hesitation in bringing him on."
Early signs suggest Bennett is likely to be out for weeks rather than days.
But the news will not dampen the mood at Posh, who sit top of the League One table.
"The lads were up for it, they all watched the TV in there and they were very happy to see themselves top of the league," Johnson added.
"That was our brief in pre-season, to be top of the league very quickly and it's nice to be there after six games."
Johnson's side head to Exeter on Saturday looking for their second away win of the season.
What are these?
Print Sponsor
Bookmark with:
What are these?