McCoy, the NFL's second-leading rusher, could miss further time depending on how the injury heals, Anderson said. The Bills host the Patriots in Week Eight and are at the Seahawks in Week Nine before their bye.
Mike Gillislee is in line to take over as the Bills' top running back with McCoy out, with Reggie Bush and rookie Jonathan Williams filling in behind him.
I'm told #Bills RB LeSean McCoy (hamstring) is not playing this Sunday and could miss more time thereafter, depending on healing.
— Josina Anderson (@JosinaAnderson) October 20, 2016
Since the switch to Anthony Lynn at offensive coordinator after Week Two, Gillislee has rushed 17 times for 116 yards a touchdown. That's good for 6.8 yards per attempt, which would be leading the league if he had enough rushes to qualify. Even without his 44-yard touchdown last week against the 49ers, Gillislee would still be averaging 4.5 yards a pop, well above the league average of 4.1.
McCoy was slowed by a left hamstring injury during last year's preseason and later sat out two games to try to get closer to 100 percent, telling reporters he had a Grade II strain. Bills coach Rex Ryan said he didn't know which leg McCoy injured Wednesday.
Ryan had said earlier Thursday he was "hopeful" McCoy could play Sunday.
"I know it scares every Buffalo Bills fan" to hear McCoy paired with a hamstring injury, Ryan admitted. "Right away, we go back to last year and things. Hopefully it’s not to that extent. I don’t believe it is."
Lynn, though, seemed less optimistic he'd have McCoy Sunday.
"I don’t want to do what we did last year," the offensive coordinator said. "I don’t want him playing 85 percent, reinjuring the hamstring and then this thing lingers all year. So you just want to get him well, get him back on the field. ... Last year, it was a week-to-week thing and I don’t want to do that anymore. I want him on the field healthy and ready to go. I want him to be LeSean."
The Bills' rushing attack has surged to No. 1 in the NFL in both total yards and per play under Lynn. He said he wouldn't change anything if he didn't have McCoy.
“The running game, it won’t change. And the way we call plays won’t change," Lynn said.
"Mike he has shown what type of running back he is. You know, he’s been highly productive for us and he’s been a solid backup, and I have all the confidence in the world that if his role has to increase, then he’ll do a good job.
"I think any backup is itching for opportunities," Lynn added. "But Mike has worked hard and he’s prepared, and if he’s got to step in as the number one guy, I have a lot of confidence in him.