Iginla suffered the injury midway through the second period of Thursday's 5-4 win over the Florida Panthers. Iginla said Friday it happened when he was hit by Bryan Allen.
"I remember trying to get by him and my leg got hit," Iginla said. "I doesn't feel great today, but it's the first day. I'm always hopeful, always trying to heal quicker and I'm always holding out hope."
The winger leads the Flames in scoring with 23 goals and 30 assists in 39 games.
Iginla's sprained medial collateral ligament will be re-evaluated in a week.
"It's MCL and there's no surgery or anything like that and that's a good thing," Iginla said. "It's sore today and we'll see what they say in a week."