Dahlin and Hedman will be the headliners when the Buffalo Sabres and the Lightning play at Ericsson Globe on Friday (2 p.m. ET; NBCSN, SN1, NHL.TV) and Saturday (1 p.m. ET; NHLN, SN1, SUN, MSG-B, NHL.TV).
Hedman is back in the Lightning lineup after sustaining a lower-body injury against the New York Rangers on Oct. 29.
So barring a setback for Hedman, it will Dahlin, the Sabres' No. 1 pick of the 2018 NHL Draft against Hedman, the No. 2 pick of the 2009 NHL Draft. It will be a 19-year-old rising star who was a finalist for the Calder Trophy as NHL rookie of the year last season against a 28-year-old established star who has been a finalist for the Norris Trophy as the best defenseman in the NHL three times, winning it in 2018.
It will be a dream come true.
"I'm here in the NHL too, so I can't think about it too much," Dahlin said. "But it's awesome. It's really cool to play against him."
And vice versa.
Dahlin had 44 points (nine goals, 35 assists) in 82 games as a rookie last season and has 11 points (one goal, 10 assists) in 15 games this season. Hedman had 20 points (four goals, 16 assists) in 74 games as a rookie in 2009-10 and has nine points (two goals, seven assists) in 11 games this season.
"He's a great overall guy, the talent is out of this world, and he's producing on a high level to start the season," Hedman said of Dahlin.
"He's just going to become better, and that's pretty scary. So for me, it's all about keep pushing my game and keep competing against those guys. It's awesome, and I enjoy that. That's going to keep pushing me for a long time, hopefully."
This has been a whirlwind for Dahlin, coming home, seeing family and friends, dealing with extra attention.
After the Sabres arrived and practiced Monday, he took a group of his teammates to Max, a Swedish fast-food restaurant. But he has been spending so much time away from the team that his usual road roommate, forward Casey Mittelstadt, said he hasn't seen him much.
When he came off the ice during the Sabres' open practices at Ericsson Globe on Thursday, kids were leaning over the rail, shouting his name.
"I think he's just as excited to be home as the kids are to see him, I think," Mittelstadt said. "He's loving being here. He was super excited to come."
The Sabres made sure to talk to him well ahead of time about the demands and distractions so he would be prepared to perform well in two important Atlantic Division games.
"He's excited to play," Sabres coach Ralph Krueger said. "That's what he needs to be. He needs to have fun through these two games and just play his game. We're keeping it simple, and he is too. It'll be a wonderful opportunity for Sweden to see him firsthand. We feel he's in a really good space here."
Hedman has been through more big NHL events, such as the 2015 Stanley Cup Final and the 2017 NHL All-Star Game.
Still, he has been busy like Dahlin, playing tour guide for his teammates, seeing his family and friends, soaking up every second of this. Kids were shouting his name too. One held a homemade sign with hearts saying he was the best in English and Swedish.
And he has never played an NHL game in Sweden before, either.
"I'm starting to get a little bit nervous, and I usually don't get nervous before games," Hedman said. "But this is a once-in-a-lifetime opportunity to come back home and play for the team that I've been a part of for over 10 years. It's going to be an emotional couple of days playing in front of friends and family and the Swedish … the people and the kids, the boys and girls, that were there for this practice and will be at the game tomorrow.
"It's going to be a lot of fun."
NHL.com staff writer Jon Lane contributed to this report