Miami Dolphins quarterback Chad Pennington has been initially diagnosed with a torn capsule in his throwing shoulder and the Dolphins expect him to miss the rest of the season, sources familiar with the injury he suffered Sunday told ESPN Senior NFL Analyst Chris Mortensen.

Pennington will seek a second opinion from orthopedic specialist Dr. James Andrews, who has performed two shoulder surgeries on the quarterback.

Pennington underwent tests Monday on his right shoulder, which he hurt early in the third quarter of Sunday's 23-13 loss at San Diego. He missed the rest of the game, and coach Tony Sparano said he didn't know how long Pennington will be sidelined. Pennington has already had surgery on the same shoulder in 2004 and 2005.

Chad Henne, who went 10 for 19 for 92 yards with an interception, will likely make his first NFL start Sunday when the winless Dolphins play host to Buffalo.

"We're going to have to go out there with Henne, who is a lot less experienced," tight end Anthony Fasano said. "There is definitely going to be a learning curve for Henne. He can learn as much as he wants in a classroom, but until he's out on the field, in-game experience he's not going to learn.

"But we have a lot of faith in Chad. He's a smart guy, a great leader and fun to play with. We're just going to have to move on."

A second-round draft choice in 2008, Henne has been considered Pennington's heir apparent for more than a year. The challenge for the offense will be to develop a chemistry with Henne, receiver Greg Camarillo said.

"Chad [Pennington] is our leader," Camarillo said. "Any injury to him is an injury to our offense. But it's also an opportunity for Henne to step up. We've got faith in his quarterbacking abilities. It's time for him to show it off."

The score was 3-all when Pennington was hurt on a hit by linebacker Kevin Burnett as he threw a pass. The injury appeared to occur with the contact, which caught Pennington in an awkward position, rather than when he hit the ground, Sparano said.

"Kind of a weird-looking deal," Sparano said.

Linebacker Joey Porter, nursing a sore right hamstring, also was unable to finish the game because the muscle tightened. Sparano said Porter will be further evaluated this week.

The injuries are another blow for a team rapidly regressing after a great leap forward in 2008, when the Dolphins improved their victory total by 10 games and won the AFC East. Now they're 0-3, and only three teams since 1990 have gone to the playoffs after such a slow start.

Sparano said lineup changes are possible.

"I told this team yesterday, it's not OK to be 0-3," he said. "It's not acceptable. If there's a place where we can shake some things up, we will."