The Senators right wing crashed hard into the end boards behind the Ottawa net late in the third period while skating at full speed. He lay on the ice for about a minute before being helped to the dressing room while appearing to be favoring his right side.
However, Ryan told coach Paul MacLean after that game that he'll be fine, the Ottawa Sun reported.
MacLean told the media he wasn't sure of Ryan's condition.
"It's kind of up in the air," he said after the Senators' 3-1 loss in Dallas. "It's not something that's definite. It's just a re-aggravation of something. We'll see how it is Sunday."
Ryan saw 16:10 of ice time before the injury. He has 23 goals but has scored once in the past 10 games.
The Senators continue their road trip Monday night against the Tampa Bay Lightning.