According to Dr. Harjas Grewal, the worry is about Kakko's knee and whether or not it's a medial or high ankle sprain. The amount of time Kakko is likely to miss depends on the grade of the sprain, but, the time frame for his return would be about 4-6 weeks. The other worry would be Kakko's MCL. Again, time frame would depend on the grade of the injury
Kakko, 21, has not produced well this year. In 40 games with the Rangers this season, he has 7 goals and and 9 assists for 16 points.