In 2017, after the Washington Nationals lost by one run at home in the deciding game of a divisional round playoff series for the second year in a row, Bryce Harper packed his things and took a five-hour flight home with relief pitcher Brandon Kintzler, a fellow Las Vegas native and resident.

“He was young and just newly married,” Kintzler recalled by phone last week. “I think we had [veteran outfielder] Jayson Werth to kind of keep him in line.”

And now?

“I’m anxious to see,” said the 36-year-old Kintzler, who recently signed with the Phillies and is competing for a job in spring training. “He’s definitely a family man now. I’m anxious to see how he acts and how he goes about his business.”

Call it a hunch, but Kintzler likely will spot a difference.

As the Phillies gather for their first full-squad workout Monday in Clearwater, Fla., it’s striking how much Harper’s life has changed in the 725 days since he joined the Phillies. It isn’t only his 13-year, $330 million contract, still the record for free agents. He has also become a father -- of two. His son, Krew, was born in August 2019, and his daughter, Brooklyn, this past November.

Harper is 28 now, which hardly seems possible considering he has been in the baseball zeitgeist since he appeared on the cover of Sports Illustrated at age 16 as the “Chosen One,” a distinction that invited as much jealousy and scrutiny within the sport as it did admiration. Phillies manager Joe Girardi joked Sunday that Harper “was [called] up when he was 12 years old.”

There are times when the Phillies’ star right fielder doesn’t act his age. He’s an avid gamer with an affinity for Fortnite. But he’s as likely to post pictures of his kids on social media, a sign that he’s in a decidedly different phase of both his life and career.

“I think he has a great balance in life,” Girardi said. “He’s a great husband, he’s a great father, which obviously, if you’re not around him, you wouldn’t know that. But I got a chance to witness it last year.”

With the Nationals, Harper was the kid with impossible expectations. Leadership wasn’t required in a clubhouse filled with older position players, including Werth, Ryan Zimmerman, Ian Desmond, and Daniel Murphy. But baseball also fosters a culture in which younger players are supposed to be more reserved. Harper’s overt displays of emotion on the field didn’t always sit well. In 2015, he fought with closer Jonathan Papelbon in the dugout.

By the time Kintzler joined the Nationals at the trade deadline in 2017, the conversation centered around Harper’s long-term future with the team. Harper grew tired of questions about a contract extension or potential trade.

There’s no question about Harper’s status with the Phillies. In a division filled with face-of-the-franchise superstars -- Freddie Freeman and Ronald Acuna in Atlanta; Francisco Lindor in New York; Juan Soto, in Washington -- Harper is the Phillies’ marquee player. He has 11 years left on a contract that will take him through his age-38 season, and he’s as invested in the Phillies as they are in him.

Harper isn’t shy about sharing his opinions. He campaigned so vigorously for the Phillies to bring back J.T. Realmuto that the star catcher could have considered giving him an agent’s commission after signing a five-year, $115.5 million contract. He lobbied for Spencer Howard to be in the rotation last season. During the draft last June, he asked then-general manager Matt Klentak for each Phillies draftees’ phone number after they were picked, then FaceTimed them.

And although he and Kintzler live on opposite sides of Las Vegas and rarely cross paths in the offseason, Harper helped convince him to sign a minor-league contract with the Phillies and come to spring training to fight for a spot in a bullpen that needs help.

“I feel like, through texts and talking to him from across the field last year, that he’s a more mature kid and he’s here to do his job and he realized what’s important,” said Kintzler. “It seems like he’s willing to trust his teammates more, and I think you’ve got to evolve to do something like that.”

Girardi thinks Harper might still be improving as a player, too.

Harper’s first two years with the Phillies have been excellent, if unspectacular. Among 226 players with at least 500 plate appearances since the start of the 2019 season, he ranks 12th in on-base percentage (.385), tied for 16th in home runs (48), and tied for 20th in OPS (.903). He was in the midst of an MVP-worthy season last year, batting .343 with seven homers and a 1.192 OPS through 22 games before a back injury drained his power and sent him into a three-week tailspin.

According to Girardi, Harper is healthy as camp opens. Back problems can be tricky, though, and given how hard Harper plays, Girardi said the Phillies might have to rein in their superstar in spring training.

“Bryce is always studying the game and trying to figure out how to get better,” Girardi said. “If you look at his first month [last year], if he does that over the course of a season because he’s healthy, he’s going to have a monster year. It really is [about] keeping him healthy.”

Kintzler is eager to see it.

“He can only get better,” Kintzler said. “I’m anxious to see what Bryce is like now that he’s got a family, he’s the guy, and this is his team.”