Grossman has five assists in 52 games this season with Dallas.
The 27-year-old entered the league with the Stars in 2006 after being drafted by Dallas in the second round (56th overall) of the 2004 entry draft. In 333 career games, he has scored three goals and assisted on 38 more.
"He is experienced, he is a bigger body and he is a good solid defensive defenseman," Flyers general manager Paul Holmgren said. "He can kill penalties for us and play regular shifts. He can chew up minutes. Like I said, he is a big body."
In exchange for Grossman, the Stars received a 2012 second-round pick and a 2013 third-round pick.