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.