Mornings began at 5:30 a.m., well before the sun. Eight-year-old David Peterson would wake up, go to the barn and watch his father work. There was much to be done, training horses for events at nearby Santa Anita Park or Hollywood Park Racetrack. Mornings started early for a reason.

Summers were spent down south, at Del Mar, where Peterson would go to see the horses race. This was decades after Seattle Slew, his dad’s most famous pupil, went to stud. David Peterson has watched all the old movies, all the old documentaries about the Triple Crown winner, but the newer horses were the ones he was able to view up close, seeing their power and discipline, and understanding at a young age all the toil that went into it. For Peterson, races weren’t measured in minutes and seconds. They were measured in 5:30 a.m. wakeup calls and training regimens and sweat and effort.

Then tragedy struck and Peterson’s life changed forever. Gone was the barn, gone were the racetracks, the horses, the carefree summers. It would be a decade and a half before Peterson, at the age of 24, would fulfill his own dream of becoming a professional baseball player, starting games for the Mets at Citi Field.

At 9, still a child, Peterson was consumed by loss. At 9, Peterson was forced to grow up faster than anyone ever should.

“It was devastating,” Peterson said, “being a 9-year-old kid and having my mom look at me and telling me that my dad, the main male figure in my life, is gone and isn’t coming back.”

***

Behind every stoic is a story.

From his first day as a Met, Peterson has seemed unflappable. When Mets manager Luis Rojas told him that he would make his Major League debut last summer, Peterson offered no outward emotion. He simply thanked his manager, told him he was ready, then pitched well into the sixth inning of a win over the Red Sox at Fenway Park. Peterson would go on to produce a 3.44 ERA over nine starts and a relief appearance, positioning himself as a key rotation member heading into this season.

Part of that was due to Peterson’s nature -- quiet and determined. Part stemmed from the circumstances that had shaped him as a youth.

Doug Peterson spent his entire adult life around horses, earning his training license by age 18. His break came eight years later, when he became Seattle Slew’s trainer shortly after the legendary racehorse swept the 1977 Triple Crown. Off-track problems took Peterson out of the game for two and a half years, according to a 1988 Los Angeles Times profile, but he eventually returned to the training business and found additional success.

By the time David Peterson was born in 1995, his father had re-established himself as a prominent trainer, leading horses to victories across the Southern California circuit. Father and son bonded over racing, with the younger Peterson arising each morning to help in the stables.

That was life for a time, until heartbreak worked its way into Peterson’s orbit. When he was 7, his father was seriously injured in a golf course accident. Eighteen months later, Doug Peterson was found dead of an accidental overdose stemming from a medical error.

Nothing could have prepared his son for the profound ways in which his shattering world would alter him.

“It instilled a heightened sense of accountability and responsibility for myself,” David Peterson said. “And I think being able to have male figures -- like my mom’s dad and other people to kind of fill that gap when my dad passed -- was also a big part for me. I’ve always been able to lean on my family through hard times.”

The Petersons eventually moved from California to Colorado, where David developed into a standout amateur baseball player. By the time he was a junior in high school, Peterson believed he had established enough Draft momentum to forego college and turn pro. He was going places. At a Perfect Game showcase in San Diego, Peterson caught the eye of University of Oregon coach George Horton, who wanted to sign him but didn’t believe he’d be able to lure the pitcher to campus.

Once again, circumstances rapidly changed. Two weeks before the start of his senior season, during a team retreat, Peterson pushed off for a layup in a pickup basketball game and snapped his right fibula in two places. The left-hander recalls looking down and seeing his ankle bent at a sideways angle. In a hospital bed across the street, he became emotional, knowing what six weeks away from baseball would do to his Draft stock.

Then, Peterson steeled himself against the misfortune.

“Looking back now, it’s one of the biggest blessings I see in my life because it gave me the opportunity to really focus on getting better,” he said. “For me, it was really about, ‘OK, let’s move forward.’”

Six weeks to the day after breaking his leg, Peterson was back on the mound in a high school game. It was not enough to prevent him from falling to the 28th round of the 2014 Draft, but fate’s twists are not always easy to anticipate in the moment. No longer looking at a life-changing signing bonus, Peterson instead joined Horton at Oregon, where he developed both physically and mentally over three seasons. As a junior, Peterson struck out 140 batters in 100 1/3 innings, including 20 in a game against Arizona State. He became an All-American. He re-entered the Draft. The Mets selected him 20th overall in 2017.

“He handled his priorities and his responsibilities like a pro, like a man,” Horton said. “That’s the best thing I can say about anybody is that they were never substandard to our standards. And our standards were pretty significant.”

***

When Mets pitcher Carlos Carrasco suffered a right hamstring strain earlier this month, any lingering doubt over Peterson’s rotation status vanished. Despite staying cognizant of their need to limit Peterson’s innings in what will be his first full season, Mets officials understand that he is one of their five best healthy starters. Rojas has all but said as much publicly. And so Peterson is likely to be in the Mets’ Opening Day rotation.

Horton does not doubt what his former ace will do with the opportunity. Nor do others close to Peterson, who has already handled so much adversity in his life that the obstacles currently facing him -- inning totals, durability, velocity, sharpness -- seem small by comparison.

These are the lessons Peterson has learned through loss and from the strength of his family in the years following Doug Peterson’s death.

“A lot of times, as we know, people use tragedy to fall into a trap of making some bad choices as they grow up and then pointing to that as a reason,” Horton said. “I don’t know that period of time in his life other than I know he came through it -- I wouldn’t say unscathed, but with flying colors.”

Horton paused for a moment before continuing: “And, well, what a kid.”

Since his father’s passing 17 years ago, Peterson has been back to the old Southern California racetracks a few times, absorbing what emotion and nostalgia remain. He’s itching to get to the Kentucky Derby one of these years, even if that may have to wait until his playing career is complete. At some point, Peterson might consider investing in his own horses, though that’s a thought for another far-off day.

For now, his mind is on baseball, and the Mets, with the difficult lessons of Peterson’s past casting a light across his future.

“To go through something like that at such a young age and having to move forward, I think that definitely plays a part,” Peterson said. “It’s just a culmination of life experiences that I’ve had, and ups and downs, and being able to find my way out and know that there’s light at the end of the tunnel. And just finding your way out of that tunnel.”