Mikael Backlund, who was just beginning to emerge as a bona fide top-six forward for Calgary, suffered a sprained knee in Thursday's 4-3 overtime victory over the Columbus Blue Jackets and will be out at least a month. The 23-year-old center was placed on injured reserve Friday. For Backlund, who had scored three times in his first eight games, it's his third significant injury since the beginning of last season.The Flames' first-round pick in the 2007 NHL Entry Draft missed nearly six weeks after breaking a finger in training camp in 2011-12. Then the skilled Swede suffered a season-ending shoulder injury in mid-February. "Thnx for all the great support #CofRed. I hope to be back ASAP and help the team making the playoffs!" Backlund wrote Friday evening on his Twitter account. According to the Flames, Backlund is officially out four-to-six weeks due to a Grade 2 sprain of his MCL. That's a mouthful of medical mumbo-jumbo. It's also a big chunk of action in a condensed schedule. If Backlund is, indeed, sidelined for the full six weeks, he'll miss 20 games. "Obviously, it's disappointing," said Flames GM Jay Feaster. "It's disappointing for him. He's frustrated."