SCOTTSDALE, Ariz. >> The big wigs were on hand for this one.

Farhan Zaidi looked on from the first base dugout. New general manager Pete Putila was a few feet away. Stationed behind the mound: manager Gabe Kapler and a collection of other coaches. What were they gathered here to see Friday afternoon, on the second day of spring training?

The future, they hope.

It was the first live batting practice session of camp, and their presumptive Opening Day starter was kicking things off. But the crowd, which included a half dozen other pitchers watching from the dugout railing, was here to see the young man who followed Logan Webb — who they hope will follow Webb in the rotation for years to come — 21-year-old Kyle Harrison, the top left-handed pitching prospect in the game.

“He’s definitely got a lot of talent,” said catcher Joey Bart, who met the young lefty for the first time Friday and was one of four hitters he faced during one-plus simulated innings. “He’s got a really good fastball for a kid that’s, what, 21? Just a lot of talent, just a lot of upside.”

The Giants are banking on that upside to give them a two-headed monster at the top of their rotation for years to come, and they believe the talent there is already enough that he will start the year with Triple-A Sacramento and could be on the fast track to the majors.

Using his fastball-slider combo (and working to refine a changeup), Harrison struck out more batters than all but one pitcher in the entire minor leagues last year. He limited batters to a .196 average against him and finished with a 2.71 ERA in 25 starts between High-A and Double-A.

Almost as soon as it was over, Harrison headed for Arizona, where he spent the entire offseason training at the Giants’ Papago Park complex, often in tandem with Webb, who owns a home here. They pushed each other in the weight room and built a relationship. At fan fest earlier this month, Webb couldn’t stop himself from raving about the young buck.

Webb, Kapler said, “recognize(s) how important he is to the future of our organization, take(s) that responsibility very seriously, and that means taking some of the younger pitchers under his wing.”

Harrison smiled as he delivered each pitch.

He met with a group of reporters for the first time afterward and grinned through most of his answers.

The Giants want to see him throw strikes more consistently. On Friday, all that seemed to matter was that he was here.

“I’d be lying if I said I didn’t have any nerves,” Harrison said. “… It wasn’t (my) best stuff. I want to throw more strikes. That’s a big goal for me this year. Keep attacking hitters. Slider wasn’t how I liked it today, but it’s early.”