Hayes immediately joined the Panthers after the trade and played in the last four games of Florida's five-game road trip.
Olsen had been playing with the San Antonio Rampage of the American Hockey League until he was called up on Sunday.
One thing Hayes and Olsen bring to the Panthers is some size, with Hayes standing 6-foot-6 and Olsen standing 6-2.
"It's hard to teach size," Panthers interim coach Peter Horachek said after the morning skate Monday. "They're big, solid guys. That helps. They're good kids. (The) youthful size and that energy that they bring, I think, is really positive."
Olsen appeared in 22 games for the Blackhawks in 2011-12, but spent all of last season with the Rockford IceHogs of the AHL. Ironically, his first NHL game also came against the Flyers.
Olsen made his NHL debut on Jan. 5, 2012 in a 5-4 Chicago loss against the Flyers, playing 9:48 and finishing with three shots on goal.
The defenseman's most vivid memory of that game, however, involves a run-in with Flyers forward Wayne Simmonds.
"Simmons tried to run me, threw an elbow," Olsen said. "Other than that, I remember I had quite a few shots, couple of scoring opportunities. Hopefully I can do that again tonight and put one in the back of the net."
In Florida's last game, a 4-3 shootout loss against the Calgary Flames on Friday night, Hayes scored his first goal in a Panthers uniform.
"It's like a huge relief to get one early here and just get everything going in the right direction," Hayes said. "I feel like I can score some goals. That's what they're expecting of me, to be physical and bring energy, and [scoring] goals, that's just a bonus."
Along with Olsen, the Panthers' defense corps also should be bolstered by the return of veteran Mike Weaver, who missed the past four games because of an illness.
Weaver was put on injured reserve Sunday to make room on the roster for Olsen, but the move was retroactive and Horachek said he was expecting Weaver to be in the lineup Monday night.
As of Monday afternoon, the Panthers had yet to activate Weaver or clear a roster spot for him.
The Flyers, meanwhile, figure to go with the same lineup that has helped produce a 6-0-1 record over the past seven games.
Increased production on offense has led to the turnaround. Philadelphia has scored 27 goals in its past seven games after scoring only 22 in its first 15.
"They're shooting the puck," Flyers coach Craig Berube said. "We've got a good rush attack going right now. We're starting to figure out the [offensive] zone part of it. We're doing a good job using our D. Everybody is involved in it, which is important. When we get pucks and people to the net, good things happen. That's what we're doing."
Here are the projected lineups for the Flyers and Panthers on Monday night at BB&T Center:
Notes: Kopecky and Winchester will each miss his second consecutive game after being injured during a 4-1 loss against the Edmonton Oilers on Thursday night.
Jovanovski continues to practice with the Panthers during morning skates, but Horachek said the veteran defenseman and team captain isn't quite ready to make his season debut after undergoing offseason hip surgery.
"He's progressing," Horachek said. "The doctors, him and the trainer, they're working out the progress. This is not a simple situation. There's a lot of healing in the inside that has to get to a certain point. If you rush it back, you're going to have setbacks. You don't want that. You continue to make sure that it's completely at a point where he can take all the pounding of a regular hockey game."