Zach Mettenberger to start at QB in place of Marcus Mariota for Tennessee

Tennessee Titans rookie Marcus Mariota will not play Sunday against Atlanta as he recovers from a sprained MCL in his left knee. Zach Mettenberger will start at quarterback.

Coach Ken Whisenhunt said Friday that Mariota has been ruled out after missing practice all week and the rookie’s knee has not quite healed up. Mettenberger practiced as the starter in Mariota’s absence.

Mariota sprained the medial collateral ligament in his left knee when hit low by Miami defensive end Olivier Vernon in last weekend’s 38-10 loss to the Dolphins.

Mettenberger started six of the seven games he played last season as a rookie. The sixth-round draft pick out of LSU still is looking for his first career win, and he threw for 1,412 yards with eight touchdowns and seven interceptions last season.

The Titans also will be without wide receiver Harry Douglas (ribs) and starting cornerback Perrish Cox (hamstring).

Dez Bryant doubtful for game against Giants

Dez Bryant didn’t travel with the Cowboys to New York, making it less likely the All-Pro receiver will return from a broken right foot against the Giants.

Bryant was listed as doubtful Friday after missing practice all week. He broke his foot in the opener against the Giants, a 27-26 Dallas victory. The rematch Sunday will be six weeks since Bryant’s injury.

A team spokesman said Bryant could travel Saturday. The team left a day earlier than usual to visit the 9/11 memorial.

Johnny Manziel likely to remain Browns backup during probe

Johnny Manziel is expected to remain the Cleveland Browns’ backup quarterback as the NFL investigates whether he violated its personal conduct policy.

Manziel was questioned on Oct. 12 by police in Avon, Ohio, after he and girlfriend Colleen Crowley argued while the 2012 Heisman Trophy winner drove on a highway. Crowley told police that Manziel hit her several times.

Manziel denied striking Crowley, was not arrested and the couple was allowed to leave together. Manziel could be facing a fine, suspension or potential banishment if the league finds he broke provisions in its conduct policy.

DeSean Jackson’s home in Tarzana is robbed

Police say four people invaded and robbed the Tarzana home of Washington Redskins receiver DeSean Jackson.

The Los Angeles Police Department confirmed Friday that the invasion occurred at Jackson’s home in the Tarzana area. Police said four robbers invaded Jackson’s home early Wednesday morning, when five people were home, though Jackson was not among them.

Etc.

Linebacker DeAndre Levy and tight end Brandon Pettigrew will miss Detroit’s game against Minnesota on Sunday. Levy has a hip injury. Pettigrew has injuries to a knee and elbow. Cornerback Josh Wilson (concussion) is questionable. ... San Francisco safety Antoine Bethea was placed on season-ending injured reserve Friday with a shoulder injury suffered in Thursday night’s 20-3 loss to Seattle. ... Kansas City Chiefs wide receiver Jeremy Maclin has passed the league’s concussion protocol and should be available for Sunday’s game against the Pittsburgh Steelers.