MESA, Ariz. – During an escalating prank war, Ryan Dempster once arranged for a camera crew to shadow Will Ohman in spring training and sell the journeyman reliever on being the star in a TV special.

But Dempster isn't trying to punk anyone by playing for Team Canada in the World Baseball Classic – even though he's almost 40 years old and hasn't pitched in a competitive environment since Game 1 of the 2013 World Series at Fenway Park.

Don't let the Harry Caray/Will Ferrell impersonations fool you. Dempster always had a different side to his personality, an edge that allowed him to recover from Tommy John surgery, transition from 30-save closer back to All-Star starter and throw nearly 2,400 innings in The Show.

Still, it sort of felt like a reality show or a time machine or a spin-off from a Kris Bryant Red Bull ad on Monday at Field 1, the most secluded spot to throw live batting practice at the Sloan Park complex. On a cool, gray day, Dempster looked the same with his reddish beard, glove waggle, white pinstriped pants and blue Nike cleats.

Before stepping into the batter's box, Cubs president Theo Epstein tried to talk a little trash with Dempster: "I know I can't hit big-league pitching, but I'll see if I can hit you."

Besides Epstein, the eclectic group of hitters included Tommy La Stella and minor-leaguer Todd Glaesmann. Dempster threw roughly 50 pitches to Lance Rymel, a former farm-system catcher who will manage a Dominican summer league team this year. The audience included one reporter, six fans, a group of curious Cubs staffers and reliever Jim Henderson, who is in camp on a minor-league deal and will also pitch for Team Canada.

"I'm not going to be disrespectful to the whole process," Dempster said. "I'm not just like playing in a beer league and then decide: 'Eh, I'll throw against the Dominican team. The U.S. looks like they're pretty stacked, but I'll be all right.' I know what it entails going into this.

"At the end of the day, I'm not so worried about velocity. I'm worried about command and my ability to change speeds. It has been pretty funny to see the reactions, and I can understand why people would see it as far-fetched. But I always liked a good challenge."

Dempster first hatched this idea during a Fourth of July vacation, somewhere around Sequoia National Park in California. The group included Ted Lilly – another pitcher who got by with guts and became a special assistant in Epstein's front office – and former bullpen catcher Corey Miller.

"I just said: 'For old times' sake, why don't I throw a side?'" Dempster recalled. "I thought for sure when I woke up the next day I wouldn't be able to lift my arm up. And it felt really good."

Dempster continued with a throwing program – even through a trip to Hawaii after the World Series – and contacted Greg Hamilton, the head coach and director of Baseball Canada. As a Cub, Dempster had been the one leading runs up Camelback Mountain and showing younger pitchers like Jeff Samardzija how to train for 200 innings.

"I wasn't sure if he was serious or not," said Epstein, who did make contact against Dempster. "And then when I figured out he meant it and had a plan, I knew he'd be fine, because he's such a hard worker and he's really smart. If he's going to put the time in to get ready, I knew he'd be fine. He'll be competitive, for sure."

Dempster understood how to put together his own program with a focus on his legs, strengthening his core and shoulder exercises. To be clear, this isn't setting the stage for a comeback, the way game-over closer Eric Gagne is hoping to use Team Canada as a launching pad (after not pitching in the big leagues since 2008).

"This is just a chance to represent my country," said Dempster, who grew up in British Columbia and played on junior national teams in the 1990s. "Sometimes – I'm not bored – but a challenge in life or an opportunity presents itself. (And) it's a good lesson to teach my kids: If you work hard at something, you can do (it) and hopefully it pays off."

Dempster went out on top as a World Series champion, walking away from $13.25 million rather than pitch for the Boston Red Sox in 2014. He signed on with MLB Network and rejoined the Cubs as a special assistant in baseball operations. If he had to pick a lane, it would probably be entertainment and building off his Cubs Convention late-night format and sketches like "The Newlywed Game" with Epstein and general manager Jed Hoyer.

But Dempster still needs a fix. The star-studded cast from the Dominican Republic – Robinson Cano, Manny Machado, Adrian Beltre, Jose Bautista, Nelson Cruz – will be waiting on March 9 at Marlins Park.

"Major League Baseball, professional sports aren't a normal job," Dempster said. "How do you go from that extreme high, the adrenaline rush of going out there and pitching in front of 40-grand every day to…now what do you do that satisfies you? I'm trying to find that, make my way towards that. I feel like I will eventually get there."