The Miami Dolphins lost Chad Pennington to a shoulder injury, then lost another game not long after his replacement had a pass intercepted and returned for a touchdown.

St. Louis also lost its quarterback and remained winless, with Marc Bulger bruising his right shoulder and sitting up the final three quarters of the Rams' 36-17 loss to Green Bay.

Pennington was hit by linebacker Kevin Burnett after throwing an incomplete pass on third-and-7 from the Dolphins 40 on the first possession of the second half Sunday in San Diego. Slow to get up, he took off his helmet and shoulder pads once he got to the sideline and had a bag of ice on his shoulder.

San Diego's Eric Weddle intercepted Chad Henne and returned it 31 yards for a score with just less than 6 minutes to play, and the Chargers dropped the Dolphins to 0-3 with a 23-13 victory.

The Dolphins didn't know the extent of the injury. Pennington, who has a history of shoulder surgeries, said he was in a "state of shock."

"I'm truly disappointed because I know what type of work I've put in and what type of work our team has put in," he said.

Chargers linebacker Shawne Merriman also left that game early because of a lingering groin injury.

Frank Gore lasted only one carry in San Francisco's 27-24 loss at Minnesota before leaving with a right ankle injury. Hurt last week against Seattle, he left the game after rushing for 4 yards on one carry on the 49ers' second possession of the game. He limped to the sidelines and tried to walk it off for several minutes before taking a cart to the locker room.

Kevin Smith couldn't make it through Detroit's first win since 2007. He rushed for 101 yards before leaving with an injured right shoulder, but the Lions held on to beat Washington 19-14 and snap their 19-game losing streak.

The Chicago Bears were down to their third middle linebacker when Hunter Hillenmeyer left their 25-19 victory at Seattle with a rib injury. Third-year veteran Nick Roach moved inside to replace Hillenmeyer, who became the starter after Brian Urlacher was lost for the season.

Bills starting cornerback Leodis McKelvin did not return after hurting his leg in the first half of Buffalo's 27-7 loss to New Orleans.

It's not clear when McKelvin was hurt, though he entered the game with a sore ankle, which he hurt in last week's 33-20 win over Tampa Bay. The ankle injury prevented McKelvin from handling kickoff returns against the Saints.

Besides losing Bulger, the Rams also lost Laurent Robinson, their leading receiver this season, to an ankle injury on St. Louis' final drive of the first half. Safety James Butler hurt a knee early in the first quarter.