DENVER -- San Francisco 49ers center Daniel Kilgore suffered a lower left leg and ankle injury in the third quarter of the team's 42-17 loss to the Broncos on Sunday night, something coach Jim Harbaugh said "might be a break."
If it is a broken leg, Kilgore would be out an extended period of time, putting the Niners' already makeshift line in further flux as they head into a badly needed bye week.
"It's always tragic to lose a player," said quarterback Colin Kaepernick. "I don't know exactly what it is right now. Hopefully it's not something that is season-ending."
The backup center, undrafted rookie Dillon Farrell, also came out of the game for a spell in the fourth quarter after rolling an ankle, though Harbaugh said he should be fine.
Third-round draft pick Marcus Martin was the backup center in camp, but he injured his left knee in the 49ers' third preseason game and is still working his way back.
The 49ers surrendered a season-high six sacks to the Broncos.