Clark wasn't penalized for the play that occurred at 15:21 of the second period of Washington's 8-1 loss to the Flyers. The fine was handed down after the league's hockey operations department reviewed the play and determined that Clark struck Desjardins in the head with an elbow.
Desjardins was diagnosed with a concussion, joining Philadelphia captain Keith Primeau, who is also out with a head injury.
The extent of Desjardins' problem won't be known until he is tested by a neurologist. The Flyers said that won't take place until symptoms subside. Primeau is sidelined indefinitely after taking a hit from Montreal's Alexander Perezhogin on Oct. 25.
"It's something you don't like to see," Philadelphia forward Simon Gagne said Friday of the increased number of head injuries. "Hopefully the league is going to take care of it."
Defenseman Derian Hatcher said there might not be intent to injure, but there has been more reckless play.
"I honestly don't think guys try to elbow one another," Hatcher said. "Last night, the guy led more with his shoulder than his elbow. There are going to be blows to the head, regardless of what you do. Do I think last night's hit was dirty? No."
Flyers coach Ken Hitchcock said he believes that players are still making adjustments as the league adapts to new rules aimed at increasing the speed of the game.
"Any blow to the head, the league reviews it," he said. "You can argue and fight it, they're still going to make up their own mind. ... If they decide it warrants a suspension, they will do it."