49ers’ Lewis suffers 3rd concussion of season

San Francisco strong safety Michael Lewis sustained his third concussion of the season, going down during the 49ers’ game against Atlanta early in the third quarter trying to tackle Michael Turner.

Lewis, who sustained two concussions during an 11-day span in the preseason, could be sidelined for a prolonged period.

He led with his helmet on the hit Sunday and was face down on the field for several minutes while being examined. He eventually sat up and was helped off the field, appearing dazed. Athletic trainers ran a series of tests on Lewis as he sat on the sideline.

Lewis’ first concussion occurred Aug. 18 during a joint practice with Oakland at the Raiders’ wine country training site in Napa when he got hit by a fullback. He suffered another in an exhibition game at Dallas on Aug. 29, when he fell and took a knee to the helmet.

The 29-year-old Lewis, a Pro Bowl selection in 2004 with Philadelphia, is in his eighth NFL season and third with San Francisco.

Detroit Lions receiver Calvin Johnson limped off the field and the team’s training staff treated his right knee on the sideline. He was hobbled as he tried to walk after the Pittsburgh Steelers beat Detroit 28-20.

Johnson was running a route across the end zone in the first quarter when he pulled up and appeared to be in pain. He left the previous game at Chicago with a thigh injury that slowed him during practice.

Tennessee cornerback Nick Harper broke his right arm early in the third quarter and was knocked out of the game against Indianapolis.

Harper was hurt on the Colts’ opening drive after a turnover in the second half. He walked immediately to the locker room from the field, accompanied by a doctor while Harper held his arm at the wrist and wriggled his fingers. Coach Jeff Fisher confirmed the injury after the game.

The Bills’ depth at middle linebacker was depleted after starter Kawika Mitchell and backup Marcus Buggs were both carted off with leg injuries against Cleveland.

Mitchell, who did not return, hurt his right knee when he was bowled over by two Browns linemen while attempting to tackle running back Jerome Harrison on a sweep left.

Mitchell was on the field for several minutes and was unable to put any weight on his right leg as he was lifted onto the cart.

Buggs replaced Mitchell, but was carted off after hurting his left leg while covering on a punt return late in the third quarter. Browns defensive end Kenyon Coleman hurt his groin and did not return.

Kansas City left tackle Brandon Albert hobbled off the field late in the third quarter against Dallas, favoring his left leg.

Albert, a first-round draft pick last year, went to the bench and was attended to by trainers.

Also, umpire Bill Schuster left the field for several plays after a linebacker rolled up on him in the Cowboys-Chiefs game.

The Cowboys had the ball around midfield in the first quarter when Marion Barber banged into the line. Schuster was standing in front of the pile when Kansas City’s Tamba Hali rolled up on him from behind, knocking him flat. He lay on the ground for several minutes and then walked very slowly to the sideline, where he was being attended to by a Chiefs trainer. He walked up and down the sideline several times and then re-entered the game.