DAVIE, Fla. (Aug. 7, 2007) -- New Miami Dolphins linebacker Joey Porter underwent arthroscopic knee surgery for the third time in two years.

The surgery was performed by Dr. James Andrews in Birmingham, Ala., after Porter went there for a second opinion. The Dolphins had not yet received a report on what repairs were made.

"They decided to go in and take a look at it," Dolphins coach Cam Cameron said. "They do say it's something minor."

Porter is expected to be sidelined at least two weeks, and he might miss all four exhibition games. The first is Saturday against Jacksonville.

Porter has been out of action since Friday because of the injury, which began bothering him during the offseason. He received a guaranteed $20 million in March to sign with Miami after spending his first eight NFL seasons with the Pittsburgh Steelers.

Porter's replacement will be Donnie Spragan, who started nine games each of the past two years. Despite the surgeries, Porter has missed only six games in his NFL career.

Cameron said tackle Anthony Alabi's left knee injury appears to be minor. Alabi limped off the field Monday morning, but there was little minor swelling, Cameron said.

Porter, a three-time Pro Bowl linebacker, missed most of training camp and all four exhibition games in 2005 after needing left knee surgery -- a problem aggravated when he jumped to celebrate winning a training camp blocking competition.

He returned to play in all 16 regular-season games and four playoff games for the Super Bowl champion Steelers.

Porter had arthroscopic surgery on his right knee in May 2006. He went on to play in 14 games, missing two because of a hamstring injury.

After eight seasons, the Steelers released him in a salary cap move last spring. Porter signed a five-year, $32 million deal with Miami.