Halak left the Islanders' 2-1 win over Pittsburgh on Tuesday night with 4:22 remaining with an apparent groin injury. New York coach Jack Capuano announced the expected length of Halak's absence Wednesday before the team's game against the Maple Leafs.
Thomas Greiss, who finished the win over the Penguins to help Halak get his 200th career victory, will probably get the bulk of the starts the rest of the regular season and into the start of the playoffs, with No. 3 goalie Jean-Francois Berube backing him up.
"It's a big loss for our team," Capuano said. "Guys are going to get an opportunity now to step in and hopefully can do the job."
The Islanders are third in the Metropolitan Division, three points behind the second-place New York Rangers and five points ahead of Pittsburgh, which holds the Eastern Conference's top wild-card spot.
Greiss, in his first season in New York, has played well while mostly sharing the goaltending duties with Halak, going 18-6-3 with a 2.20 goals-against average and a league-leading .930 save-percentage. He began the day having won seven of his last eight starts.
Unlike Halak, who has 30 games of playoff experience, Greiss has less than one full outing. He appeared in relief of Evgeni Nabokov for San Jose in 2010.
"This is maybe something a little bit new for Thomas, too, moving forward," Capuano said. "I just know the kind of kid he is, the character that he has. He competes hard, and that's what you look for in a goaltender."
Halak, in his second season with the Islanders, is 18-13-4 with a 2.30 GAA and .919 save percentage.
The Islanders finish the regular season on April 10, and the playoffs are scheduled to begin three days later and five weeks from today.