"Clarke is devastated by this news," general manager Pierre Dorion said Friday. "He felt he didn't have any symptoms, but I think in the long-term of this process we always said that the doctors would decide if Clarke was going to play. They all feel that Clarke should not play this year."
MacArthur, who is on Long Term Injured Reserve, has had post-concussion symptoms for nearly two years but had been steadfast in his desire to return to the lineup this season. He is under contract through 2019-20.
MacArthur has 304 points (133 goals, 171 assists) in 548 NHL games with the Buffalo Sabres, Atlanta Thrashers, Toronto Maple Leafs and Senators.
Goaltender Craig Anderson could return to the Senators in late January or early February, said Dorion, who added that when Anderson returns, it is expected he will remain with Ottawa for the rest of the season.
Anderson, who last played on Dec. 5, has been with his wife, Nicholle, while she has been undergoing cancer treatments. Anderson is 12-6-1 this season with a 2.46 goals-against average and .924 save percentage.
