During every other stop in Sullivan's 17-year career the mood shifted once the long slog through the regular season ended and the chase for a Stanley Cup began.
Typically the first day back at practice in preparation for the playoffs was met with a mix of joy, relief and nerves.
"You were just so excited to get in and see what happens from there," Sullivan said.
Not in Pittsburgh, where the only difference on Monday was that there was no difference.
"Here, we expect big things from this hockey club," Sullivan said. "Today is just another day at the job."
One that won't be considered complete unless the Penguins hoist sport's most coveted Cup for the second time in four years. Pittsburgh opens the Eastern Conference quarterfinals on Wednesday against rival Philadelphia as perhaps the team to beat.
Just saying those words — and really meaning them — brings a smile to Sullivan's face.
"Everyone says it the first day of training camp, 'Our goal is to win the Stanley Cup'," he said. "But there's only a few teams that can honestly believe that and we're one of those teams. That's why I came here."
At an age when most players are into their post-career lives, the 37-year-old Sullivan is thriving. He finished with 17 goals and 31 assists while floating between lines and quarterbacking Pittsburgh's power play.
The same player limited by injuries to just 44 games during his final season in Nashville missed only three this year, one of them coming in the meaningless season finale against the Flyers.
And it's not like Sullivan is playing on the fourth line. His ice time hovered in the 14-15 minute range, a pretty heavy workload for a guy often playing alongside two of the best players in the world in 24-year-old Sidney Crosby and 25-year-old Evgeni Malkin.
Sullivan runs his hand through his brown hair — which already has a hint of grey — and just laughs when asked how a 5-foot-8, 161-pound guy survives in the NHL for the better part of two decades.
"I think my asset throughout my career has been speed," he said. "If you're not a big guy, if you don't have speed, it's tough to make a living here."
Yet Sullivan has survived in what is increasingly becoming a bigger, younger league. He sat out two full years with a painful back injury then modified his training regimen to focus on intensity, not duration. It's allowed him to keep the step he worried would disappear during his sabbatical.
"I think the guys that do (lose a step) don't stay in the league," he said. "I'm not saying I'm as fast as I was when I was 25 years old but I think if you're able to try to stay as close as you can to there. That's what keeps you around."
Being arguably the smartest player on the ice helps.
Pittsburgh coach Dan Bylsma placed Sullivan on the power play not because Sullivan has a big-time shot — he's only topped 30 goals in a season twice — but because of his feel for the game.
"I think probably more than anyone on our team, he can see the things that (Crosby) and (Malkin) are doing and what they need and get them the puck in those situations," Bylsma said.
Forward Pascal Dupuis called Sullivan's hockey IQ off the charts and his anticipation "the best I've ever seen."
It's one of the reasons Sullivan has been able to fit in so seamlessly in Pittsburgh after spending the majority of his career in Nashville, where he was one of the team's most popular players.
He's no longer a franchise cornerstone. That's fine. As good as he feels, he knows the window is starting to close. He wants to win a Cup. Now.
"He feels like he still has a lot in him to play hockey," Dupuis said. "I feel like he loves it around here as well. His family loves it. You come to Pittsburgh and you play for something every night. It brings the best out of everybody."
While the Flyers come to town with aging star Jaromir Jagr fading — the 40-year-old former MVP has just one goal in his last 15 games — Sullivan is fresh. He scored twice in a 6-4 loss to Philadelphia on April 1 and had three points in a victory over Buffalo on March 30.
He took the finale off to give him a break before what he hopes will turn into a long playoff grind. Days off were something he abhorred early in his career. Now he doesn't complain when Bylsma suggests he skip a morning skate.
"We joke around that rest is a weapon," Sullivan said. "I think that as you age you're going to be taxed for 82 games maybe a little bit quicker than the other guys. There's nothing wrong with your body, you just want to make sure you don't get to the point of fatigue where things could happen to your body."
Sullivan hardly looks tired. The thought of lifting the Cup he's spent the last 17 years chasing has a way of giving even the oldest legs a shot of adrenaline.
"The expectations in this dressing room are Stanley Cup," he said, "and anything less is going to be an extreme disappointment."