Martinek, one of New York's top defencemen this season, was injured Tuesday night during the Islanders' victory over the Rangers. He finished that game and then played the following night in a loss at Ottawa.
"Radek has been a warrior for us, maybe our most consistent defenceman," Islanders coach Ted Nolan said in a release Saturday. "It says a lot about him that he continued to play during the Rangers game and the whole game the next night in Ottawa because he didn't want to take himself out of the lineup.
"But this is the right thing for him. As much as we'll miss Radek, and we know how much he hates being out, we look forward to getting Radek back at 100 per cent."
The 30-year-old Martinek is in his fifth NHL season, all with the Islanders. He had two goals and 11 assists with a plus-15 rating, tops among the team's defencemen, while playing in New York's first 36 games.
The Islanders recalled defenceman Allan Rourke on an emergency basis from Bridgeport of the AHL on Saturday, hours before New York played the visiting New Jersey Devils.
In 29 games for Bridgeport this season, Rourke registered three goals and six assists. He signed with the Islanders in August 2005 and split time between Bridgeport and the Islanders last season.
While with New York, Rourke had one assist in six games.
Rourke also played in 25 games for the Carolina Hurricanes during the 2003-04 season and had a goal and two assists.