Since joining the Buffalo Bills last season, Spencer Johnson has been a valued member of their

defensive line rotation. His importance to the team is about to increase.

With defensive tackle Kyle Williams unlikely to play Sunday because of a sprained knee,

Johnson is expected to make his first start for the Bills against the Houston Texans.

This is not unfamiliar territory for Johnson, who started 11 games in four seasons with the

Minnesota Vikings. Nine of those starts, including two in the playoffs, came in his rookie

year in 2004.

"I play a lot with our rotation anyway, so the only difference is I'll be starting now," he

said after Thursday's practice. "It's always better to have everybody at full strength, but

with Kyle down it's my time to step up, and I'm looking forward to the opportunity."

Johnson signed with the Bills prior to last season hoping to get more playing time. Minutes

were hard to come by in Minnesota, where he spent more of his time as a backup to Pro Bowl

defensive tackles Pat and Kevin Williams.

The Bills were equally intrigued by Johnson, a 6-foot-3, 286-pounder with good athletic

ability who is versatile enough to play defensive end in addition to tackle. He's pretty stout

against the run, and has the quickness and leverage to push the pocket as an interior pass

rusher. He is a standout on special teams as well.

"I like everything about Spence," Bills coach Dick Jauron said. "He's a pretty quiet guy on

the field, but he just works. He works as hard as anybody we have play in and play out, in the

weight room, in the meeting room. He does everything you want him to do."

"He's got quickness off the ball. He's got a nice feel for the game, he knows what

[opposing offenses] are trying to do. He can pressure the quarterback as we saw last weekend.

He does a real good job, and I think he works well inside with Marcus [Stroud]. I think they

know each other and have gotten to know each other better. Really happy we have Spence."

Without Williams, the Bills' defensive tackle rotation is reduced to three with John

McCargo backing up Johnson and Stroud. That will make it difficult to keep the players fresh.

"It's going to be tough, but we've got to take care of each other, kind of feel each other

out and know when a guy needs to come out," Johnson said. "We work well together, and I don't

think that will be a problem."

. . .

. . .

Defensive end Chris Kelsay was added to the Bills' injury list after he didn't practice

Thursday due to a sore back. He is expected to start Sunday.

Williams, safety Donte Whitner (ankle), right tackle Jonathan Scott (ankle), tight end Shawn Nelson

(migraine headache) and fullback Corey McIntyre (sprained knee) did not practice for a second

straight day.

Quarterback Trent Edwards (concussion) was limited again, but he saw more work than he did

Wednesday. Also limited were cornerback Terrence McGee (knee) and safety Bryan Scott (ankle).

. . .

Texans All-Pro wide receiver Andre Johnson (bruised lung) returned to practice on a limited

basis Thursday. He and cornerback Dunta Robinson, also limited with an injured hamstring, are

expected to play Sunday.

Pro Bowl middle linebacker DeMeco Ryans (groin) and defensive end Mario Williams (shoulder)

practiced fully after being limited Wednesday. Rookie linebacker Brian Cushing (foot) and free

safety Eugene Wilson (groin) didn't practice again but likely will play.