The Chiefs fell to 1-7 with Thursday night's 31-13 loss at San Diego, their fifth consecutive defeat. They play Monday night at Pittsburgh.
Routt was one of the Chiefs' most notable free-agent acquisitions, signing a 3-year, $18 million deal to fill in after Brandon Carr left for Dallas.
The longtime member of the Oakland Raiders struggled in Crennel's defensive scheme, and been routinely beaten on long pass plays.
The roster spot opened by waiving Routt was filled by Smith, who played in Kansas City 2 years ago but who has been out of the league since the Titans waived him in August.
The NFL ruled that Carolina was incorrectly awarded a touchdown following an inadvertent whistle by an official. Panthers running back DeAngelo Williams was on his way to a 30-yard touchdown when an official, apparently anticipating Williams going out of bounds, blew the play dead. The whistle was blown with Williams at the 17-yard line. Redskins defenders had stopped chasing Williams before the whistle. The officiating crew then met and decided to award the Panthers a touchdown because the whistle had not affected the outcome of the play.
* Indianapolis head coach Chuck Pagano is winning his battle with leukemia. Pagano's physician said the illness, which has sidelined Indy's head coach for more than a month, is in "complete remission."
* Dallas owner Jerry Jones said he has "a lot of faith" in coach Jason Garrett and dismissed reports he might be interested in bringing in Sean Payton next season. The New Orleans coach was suspended for the season by the NFL for his role in the bounty scandal, and the league has taken issue with a clause in his contract extension that would have kept him in New Orleans through 2015. Payton could be a coaching free agent next season.
* Minnesota wide receiver Percy Harvin was using crutches the day after suffering a badly sprained left ankle Sunday. Coach Leslie Frazier said it was too early to tell if Harvin would play this week against Detroit.
* Buffalo starting defensive end Mark Anderson could miss another 3 weeks after having a setback recovering from left knee surgery. He had missed three games since being hurt in a loss at San Francisco on Oct. 7.
* Jacksonville re-signed guard Steve Vallos and waived running back Keith Toston. The team also signed rookie linebacker Brandon Marshall to the practice squad. Vallos signed with the Jaguars on Oct. 30 and was released Saturday. He had signed with the Eagles during training camp but was released.