Coach Craig Berube said he wanted Gustafsson - who was plus-9 with 10 points in 27 games before Tuesday - "to be a good defender and move the puck. Gus does that."
"Gus is one of my favorite players, to be honest," star center Claude Giroux said with a smile. "He's small, but he's a hard-nosed player and he's really smart out there. He reads the plays pretty good."
With Timonen sidelined - he is expected to return Thursday - the Flyers altered all three defensive pairings Tuesday. The pairings: Gustafsson and Luke Schenn, Braydon Coburn and Nick Grossmann, and Mark Streit and MacDonald.
Berube said Timonen, 39, "probably could have came and played, but I think it's important he's rested and feeling good" for the home stretch.
Giroux was named the NHL's third star of the month. Boston winger Jarome Iginla, who had a league-high 13 goals in March, and Detroit winger Gustav Nyquist (12 goals in March) were named the first and second stars.
Giroux led the NHL with 15 assists and 21 points in March, helping the Flyers compile a 9-3-2 record.
"His work ethic is really high, and that's what makes it all go for him - his hard work and competitiveness, along with his skill," Berube said. "He doesn't try to play a skill game . . . as much as he works. When you have a skill guy that works like that, they're dangerous players."
Goalie Steve Mason, rested Tuesday, will oppose his former team, Columbus, in a key matchup Thursday at the Wells Fargo Center. . . . The Flyers missed out on highly touted University of Massachusetts-Lowell defenseman Christian Folin, who signed with the Minnesota Wild. The Flyers were one of the finalists for the free agent.