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Injuries could already keep two defensive starters out of the Chiefs' season-opener against Atlanta. Now, a suspension has sidelined their best pass rusher.

Pro Bowl linebacker Tamba Hali will miss the Sept. 9 game against the Falcons without pay after violating the NFLs substance-abuse policy, the league said Monday. Hali will be fined an additional game check and be eligible to return in Week 2.

The league did not disclose the nature of the violation and Hali did not speak to the media after practice, instead issuing a one-paragraph statement through the team.

"I accept the discipline from the league and will return Week 2 of the NFL season with a commitment to erase this mistake with my play on the field and my conduct off of it," Hali said.

The Chiefs are already missing starting cornerback Brandon Flowers, who has been sidelined by a nagging foot injury, and safety Kendrick Lewis, who hurt his right shoulder in Friday night's preseason game against St. Louis. It's unknown when either of them will be back.

It's perfectly clear when Hali will return: at Buffalo on Sept. 16.

"Tamba's situation is unfortunate," Chiefs general manager Scott Pioli said in a statement. "Obviously we are disappointed and will miss him during the suspension, but the NFL's policies are very clear and we respect the league's decision in this matter."

Hali long ago established himself as the Chiefs' best pass rusher, reaching his first Pro Bowl last season alongside fellow linebacker Derrick Johnson.

The former first-round draft pick has started every game he's played the past six seasons. The past two years have been his best — Hali had 14½ sacks two years ago and 12 last season, when he helped a team ravaged by injuries to the doorstep of the playoffs.

"We're disappointed. We're disappointed for him, for the team, for the organization and the fans, but it is what it is," Chiefs coach Romeo Crennel said. "He's a guy who is very prideful, he's been a very good team member for this team, and I think the team will rally around him."

Indeed, Hali has become one of the faces of the franchise, even though he goes about his business away from the spotlight. He routinely signs hundreds of autographs for fans and is known for his charitable work in the community, but he rarely speaks to the media.

Instead, Hali lets his performance speak for itself.

He's racked up 266 tackles and 53½ sacks in his career, along with an interception and a safety. He's also forced 22 fumbles, many of them after tearing around some woebegone offensive tackle and swiping the ball from the hands of an unsuspecting quarterback.

It was little surprise that Pioli made signing Hali to a long-term deal a priority, and the sides agreed last season on a five-year, $60 million contract with $35 million guaranteed.

"You have to step up," Johnson said of Hali's suspension. "It's just like having an injury. This is the NFL, and we'll handle it like pros."

Crennel said that Hali will practice with the team throughout the preseason, but indicated that it could become a balancing act between keeping him in the rotation and making sure that the guys available for the regular-season opener are prepared.

Andy Studebaker is the first in line to replace Hali in the base defense.

He's a former sixth-round pick who has turned into a valuable backup in Kansas City, where he's started seven of the 54 games he's played across four seasons. But he's not known for putting pressure on the quarterback, something the Chiefs will sorely miss with Hali on the sideline.

"You know, we always look at guys and what's going to happen, but Studebaker has played both left and right for us," Crennel said. "We'll look the next week and half and see how it goes, and when we start preparing for the Atlanta game, we'll determine how we're going to approach it."

The other option is Cameron Sheffield, who played sparingly in all 16 games last year.

Sheffield has shown some ability to pressure the passer, but only has nine career tackles and is more likely to see time on the field in the Chiefs' sub package.

That means linebacker Justin Houston, who starts on the opposite side of the defense, will be critical to putting pressure on Falcons quarterback Matt Ryan, and trying to disrupt the timing with a talented wide receiver corps that features Roddy White and Julio Jones.

"You don't have the rush ability that Tamba brings to the table from everybody else," Crennel said, "but I expect everybody step up to provide some pass rush."