The Buffalo Bills’ depth at cornerback is being put to the test at a bad time.

On tap is a meeting with Tom Brady and the big, bad New England Patriots in Gillette Stadium, the Bills’ House of Horrors over the past dozen years.

Buffalo won’t have second-year cornerback Aaron Williams available for the game after he suffered a right knee injury in Sunday’s 21-9 loss to the Houston Texans that coach Chan Gailey said will keep him out 2-3 weeks.

“It wasn’t as bad as it could have been. He’s going to miss a few weeks, but it’s not a season-ender,” Gailey said about Williams, who had an MRI done on his knee Monday.

That’s good long-term news, but still leaves the Bills with a big hole to fill Sunday at a place they haven’t won since the 2000 season. Complicating matters is the uncertain status of veteran Terrence McGee, who missed the Texans’ game and has been a part-time player all season following surgery last season to repair a torn patellar tendon in his left knee.

McGee said he’ll practice Wednesday but will have to see how his knee responds before knowing if he’ll be able to play against the Patriots.

“That would be important. I don’t know what his status will be this week,” Gailey said.

“He had the week off and we’ll see if he can get back to practice Wednesday or Thursday, or Wednesday and Thursday, hopefully, and things are better, but I don’t know that.”

McGee played a season-high 36 snaps (49 percent) in Week Six at Arizona, but his knee did not respond favorably and he was limited to just 14 snaps (22 percent) the following week in a home loss to the Titans.

Even with the added rest of the team’s bye week, he was held out Sunday.

“To be honest, I can’t even tell you where my mind’s at right now. It’s definitely frustrating,” he said. “You definitely get mad, upset, all that kind of stuff, but at the same time you always come in here and try and work and hope for the best, really. Pray about it.”

McGee’s had good and bad weeks dealing with the soreness in his knee, but lately that’s been trending down.

“It’s something I’ve been dealing with, but at the same time you can kind of say it’s surprising,” he said. “It’s been down, down, down ... hopefully this week is one of the weeks it’s back up.”

McGee knows as well as anyone on the defense how important it will be to have as many healthy bodies in the defensive backfield as possible on Sunday. Brady holds a 19-2 career record against the Bills and has completed 65.3 percent of his passes with 49 touchdowns and just 17 interceptions.

“With Tom Brady passing the ball and the type of weapons they’ve got out there, we definitely need a healthy secondary,” McGee said.

Should McGee be unable to go, Leodis McKelvin will get his most extensive work since the season opener. McKelvin played 22 snaps in Week One against the New York Jets as the slot cornerback, but lost that role the following week to Justin Rogers.

McKelvin has seen just spot duty on defense since then, including three games where he took no defensive snaps at all.

“It’s a time I’ve been waiting on since the beginning of the season. Especially with the nickel situation, how that went,” McKelvin said. “I didn’t want it to come that way with the injury, but as far as me getting my shot, it’s time for me to step up.”

McKelvin, who has excelled as a returner, has split his time in practice between the slot and covering outside receivers.

“I’ve been playing on the outside all my life, so me playing on the outside is not a big issue,” he said. “Whatever they ask me to do, I’m going to go out there and give it my all.”

The former first-round pick has never been one to lack confidence.

“I can hold my own. That’s how I feel right now,” he said. “I feel very comfortable with what I can do coming in for us. ... I’m vey hungry.”

The Bills also have been getting rookie cornerback Ron Brooks up to speed. He made his season debut Sunday after being activated from injured reserve and made one tackle against the Texans.