Erskine was punished Saturday for a hit he delivered to Simmonds' face that sent him to the ice with a bloody nose late in the first period of Washington's 3-2 victory on Friday night.
Erskine wasn't penalized for the shot that knocked Simmonds out of the game.
"Obviously, he's got a head injury and probably a little bit of whiplash going on right now," Flyers general manager Paul Holmgren said after the game. "He seemed OK after the game. We're just going to have to wait and see how he is (Saturday)."
Based on his average salary, Erskine will forfeit $24,324.33 to the Players' Emergency Assistance Fund.
Erskine will miss two games against Pittsburgh and a matchup with Toronto. He will be eligible to return when the Capitals face Florida at home on Feb. 9.
The Flyers were already without forward Scott Hartnell (broken foot) and defenseman Andrej Meszaros (shoulder). Forward Danny Briere was playing in his fourth game this season after missing the start of the season with a fractured wrist.
Simmonds entered the game with five points in seven games this season, averaging more than 18 minutes of ice time per game.
Information from ESPN The Magazine's Craig Custance, ESPN.com's Scott Burnside and The Associated Press was used in this report.