The story of baseball is littered with notable and, in some cases, legendary father-son duos who got the opportunity to play the game they love at the highest level.

The Leiter family now has two such pairings, putting it at the center of some never-before-seen history.

On Thursday, Rangers right-handed starter Jack Leiter, the son of two-time All-Star Al Leiter, made his MLB debut against the Tigers.

• Who is Jack Leiter?

Jack’s Major League family tree contains not only his father but also Al’s brother Mark, and Mark's son, Mark Jr., who is in his fifth season in the big leagues.

So, when Jack dealt his first pitch at Comerica Park, he made Al and Mark the first MLB brothers to each have a son who made it to The Show.

This is the Leiter family business. It's basically the only one Jack, the No. 2 pick in the 2021 MLB Draft, has known.

"My mom told me that in pre-school I asked one of my classmates what team his dad played for because I just thought everybody played baseball," he said Wednesday.

The youngest Leiter’s debut will come 40 years after his father was drafted in the second round by the Yankees. Al made his first big league appearance in 1987 at just 21 years old. Although injuries hampered him throughout the early stages of his career, he soon became one of the game’s most dependable starters. The only southpaw of the four Leiter hurlers, Al averaged 191 innings per season from 1995-2004 and finished his career with 162 wins and nearly 2,400 innings under his belt. His career ended where it began -- with the Yankees -- in 2005, when Jack was 5 years old.

A two-time World Series champion, Al has a pitching career that is packed with big moments on the mound. He pitched for the Blue Jays in their Fall Classic-clinching Game 6 victory over the Phillies in 1993. He authored the first no-hitter in Marlins franchise history in 1996. After earning his second All-Star nod, he helped lead the Mets to the National League pennant in 2000.

But there’s nothing quite like watching your son on the mound.

“It is nerve-racking,” Al said in 2019. “I have to admit watching my son do something that he loves is way harder and much worse, shall I say, than whatever I did.”

Al was traded from the Yankees to the Blue Jays in April 1989, about 15 months before his older brother made his MLB debut with the Bronx Bombers. A fourth-round pick of the Orioles in 1983, Mark pitched for eight clubs over 11 seasons and recorded a 4.57 ERA through 1,184 1/3 frames.

Mark Jr. was born in 1991, ahead of his father’s second big league season. He broke in with the Phillies in 2017, four years after they drafted him in the 22nd round. But he really broke through with the Cubs in 2022 and compiled a 116 ERA+ over the past two seasons while making 104 appearances, mostly out of the bullpen. The 33-year-old has yet to give up an earned run across nine games (10 innings) this season.

“It's been a really great journey, but it's just like you and Dad always said -- you guys were still getting better into your late 30s,” Mark Jr. said to Uncle Al during an episode of MLB Central earlier this month.

It’s taken some time for Mark Leiter Jr. to make a name for himself in the Majors. Conversely, people all around the baseball world have known his cousin's name for a long time. Jack was one of the top high school prospects in the Class of 2019 and was often unhittable at Vanderbilt. To wit, he strung together 20 consecutive hitless innings over a three-start span in 2021 that included a 16-strikeout no-hitter against South Carolina.

His time in pro ball has had plenty of bumps; Jack finished with an ERA over 5.00 and a walk rate over 5.0 in 2022 and '23. But the 24-year-old has curtailed his penchant for issuing walks this season -- only three in 14 1/3 innings at Triple-A -- while leaning on his mid-to-high-90s fastball that’s foremost responsible for his 11.6 K/9 rate in the Minors. He struck out 10 batters and walked no one over six innings in his last start for the Round Rock Express on Friday.

He then learned Tuesday that he’ll be bringing that power four-seamer to the Majors. His first phone call upon hearing the news was to dad, of course.

“It was a long conversation,” Jack said, “and I was kind of blacked out. He said how proud he was, just reflecting on being a little kid in the backyard and all those special, special memories looking back of working hard from a young age. So, that was a special conversation, for sure.”