Flames general manager Brad Treliving said that Ramo has a torn ACL and meniscus damage in his left knee. Sharks forward Joonas Donskoi collided with Ramo in the third period of a Flames 6-5 win Feb. 11. Ramo's knee was sandwiched between Donskoi and the pipe.
In 37 games this season, Ramo was 17-18-1 with a 2.63 goals-against average and a .909 save percentage. He was 15-9-3 with a .912 save percentage last season for a Flames team that made the playoffs. Calgary is currently nine points out of the second wild card.
The Flames recalled 24-year-old goaltender Joni Ortio last week to replace Ramo.