"It doesn't look good," Marrone said after the game. "Right now, I'm thinking, without hearing it, without it being evaluated, that it's probably major."
However, the deadline to cut the roster to 53 players came and went Saturday, and Legursky remained on the roster.
On Sunday, Marrone confirmed that Legursky may have dodged serious injury.
"It's not long-term because we didn't put him on IR," Marrone said. "It's a positive sign [but] I still think it will be some time."
The initial thought was that the Bills were keeping Legursky on the active roster in order to place him on injured reserve with a designation to return. Doing so allows a player to come back after eight weeks, but they must first make the cut to 53 players.
But Marrone said the Bills won't put Legursky on that list, since they believe he could be back before Week 9.
Legursky, who was signed in June to compete with Colin Brown for the open left guard spot, likely will be the top interior backup on the Bills' offensive line upon his return.