He is scheduled to undergo surgery in Montreal today.
Senators general manager Bryan Murray says Ryan has been "dealing with the discomfort of this injury" since November.
Murray says Ryan had hoped he could wait until after the season to have the operation but when he aggravated the injury on the weekend, surgery became the "only option."
The Senators' post-season hopes have faded. They are eight points out of the final playoff spot in the Eastern Conference with 10 games to go.
Murray says the team is disappointed that Ryan will miss the rest of the season but is confident he’ll recover in time for a full summer of training.
Ryan has a team-high 23 goals with 25 assists this season.