Pittsburgh ? Chad Brown, a Pro Bowl linebacker for Pittsburgh 10 years ago, was signed Thursday by the Steelers to add depth and experience at what suddenly has become a depleted position.

They need him now, too – Pro Bowl linebacker Joey Porter is out for Sunday’s game against Kansas City and coach Bill Cowher said Brown will play, though mostly in pass-rush situations.

“It’s kind of a crash course in everything,” Cowher said Thursday. “I know he was here before but that was 10 years ago – there are a few cobwebs we have to unleash up there to bring him back to where we are. He’ll be out there Sunday and his participation will be based on how comfortable he is. But we won’t throw him in there right away.”

The Super Bowl champion Steelers (1-3), losers of three in a row, added the 36-year-old Brown a day after Porter and cornerback Deshea Townsend injured hamstrings during a routine midweek indoor practice. Townsend is questionable and will be replaced by second-year cornerback Bryant McFadden if he can’t play.

McFadden has made only one career start, but is best known for his touchdown-saving breakup of Peyton Manning’s pass intended for Reggie Wayne in the final minute of the Steelers-Colts playoff game in January.

Even before Porter was hurt, the Steelers were down a man at linebacker because top backup James Harrison is out after spraining an ankle during a 23-13 loss in San Diego last Sunday. Harrison made three starts last season.

Cowher said Porter’s injury could have been worse, but the Steelers aren’t certain when he will return.

“I guess it could have been better but it wasn’t a significant injury,” he said.

With Porter out, first-year free agent Arnold Harrison will make his first career start as the Steelers try to avoid their first 1-4 start since 1988. The Chiefs (2-2) have won their last two. Arnold Harrison signed as an undrafted rookie free agent in 2005 and has played in four games, all this season and mostly on special teams.

“That’s what every man’s dream is. Your first dream is to make it to the NFL, but everyone wants to be a starter,” Arnold Harrison said. “If it’s for me to start this week, I’m going to go out there and be the best Arnold Harrison I can be to help the Steelers win.”

Arnold Harrison was a former Georgia teammate of Chiefs linebacker Kendrell Bell, the NFL Defensive Rookie of the Year for Pittsburgh in 2001. Harrison’s backup will be Rian Wallace, who hasn’t played outside linebacker in an NFL game.

And here’s how bad it’s going for the Steelers injury-wise: right guard Kendall Simmons isn’t certain to start because of a burned heel that occurred while he was being treated for an ankle injury. Cowher initially said Simmons was questionable, but later corrected himself and said he was probable.

No wonder that, asked how Thursday’s practice went, Cowher said, “I’ve seen better.”

“We have done it in the past,” linebacker James Farrior said of the Steelers responding to adversity. “When times have been tough we’ve responded well, and times are tough right now, so we’ll see how we’re going to respond.”

Brown was a second-round draft pick by Pittsburgh in 1993 and made the Pro Bowl during his final season with the team in 1996, after he moved from inside linebacker to the outside to replace the injured Greg Lloyd. Brown left to sign a $24 million, six-year contract with Seattle – at the time, one of the richest given a free agent defensive player.

To make room for Brown on their 53-man roster, the Steelers released tight end Tim Euhus.