Ottawa Senators left wing Clarke MacArthur, who has battled post-concussion syndrome the past few seasons, failed his medical test at training camp, general manager Pierre Dorion said.
"Right now, we don't know much, but he won't be part of camp," Dorion told reporters without confirming that the issue is related to concussions.
MacArthur played only four games in each of the past two regular seasons, but his return to the playoffs last season was a feel-good story. He scored nine points in 19 games as the Senators advanced to the Eastern Conference finals.