ATLANTA -- Darren Balsley has served as the Padres’ pitching coach for a long, long time.

How long, exactly? Well, his pitchers from early in his career are all grown up with kids of their own -- kids who are being coached in the big leagues by, you guessed it, Darren Balsley.

When Cal Quantrill was promoted on Wednesday, Balsley achieved something of a personal milestone. Quantrill is the 253rd pitcher to take the mound for Balsley in his 17 seasons as pitching coach. He and his father, Paul Quantrill, form the first father/son duo to pitch under Balsley. Paul pitched 22 games for San Diego in 2005, his final season in the big leagues.

"It's pretty awesome," said Balsley. "I hope I don't call him Paul -- I have in the past. I'm really proud of Cal. It just shows that I'm old."

To the people around Balsley, however, it shows a whole lot more than that. Here are some of the reactions from those who work closely with Balsley:

Padres general manager A.J. Preller: "If you're coaching fathers and sons, it says you're good at what you do. It means you have a good message that you're able to adjust over a period of time. The game changes, and to be able to coach a father/son tandem, it's a testament to his abilities as a pitching coach."

Padres manager Andy Green: "It's a testament to his people skills. ... The sign of every great coach is that they continue to evolve and they continue to grow. They're not the same in 2019 as they were in 2003. Ultimately, he just relates so incredibly well with these guys. He builds confidence in him and they trust him, and it's hard to overvalue that."

Cal Quantrill: "Anybody who can coach long enough to coach a father and son is probably doing something right. He's one of those people who, any time he's talking, you just listen. ... Pops was obviously at a different part in his career, and there probably wasn't as much coaching going on. But I know he really respected him."

Balsley is the sport's second-longest-tenured pitching coach behind the White Sox's Don Cooper. He's widely regarded as one of the savviest pitching coaches in the game, and he's clearly been able to adapt his style over time to fit the modern game.

Just for fun, here are the Balsley leaderboards (with rate stats requiring a minimum of 100 innings):

Wins: Jake Peavy, 82
Strikeouts: Jake Peavy, 1,212
ERA (minimum 100 innings): Mike Adams, 1.66
Saves: Trevor Hoffman, 198
Appearances: Luke Gregerson, 323
Strikeout rate (minimum 100 innings): Kirby Yates, 38 percent
Batting average against: Joaquin Benoit, .153

It's a list that spans an entire generation of pitchers, as evidenced by the father/son Quantrill duo. This year, the 54-year-old Balsley is working with the youngest rotation in baseball. Quantrill, at 24, is the third oldest of the six starters.

Yet the Padres' 3.47 ERA is fifth in the Majors and second in the National League. Their rotation's 3.45 mark is also fifth. What is it that's made Balsley so effective for so long? Left-hander Robbie Erlin, the longest-tenured Padre, has a theory.

"His relationship with every player, it's individualized," Erlin said. "It's not one way of pitching. He knows what works for me is different from Kirby [Yates] or [Chris] Paddack. He's good at taking what we all possess and magnifying it, so it's the best we can be. It's just a gift that he has."