Occasionally a young player would answer correctly, but usually Jaffe pointed out that Harper -- now one of the most popular players in Major League Baseball -- once played for the Coyotes and starred at the Alpine Bank Junior College World Series.
"He was on the same field you are," Jaffe shared with a grin.
Jaws dropped and eyes widened for the kids, aged 5-12, then they started to play. Players and coaches participating in the JUCO World Series kicked off the week-long festivities with the MLB Play Ball kid's clinic, which scattered different skill stations around Suplizio Field.
Jaffe and a group of his players operated a power pitching station, where youngsters hurled fastballs that showed up on a sometimes-working radar display. For Jaffe, the kid's clinic at the JUCO World Series is an opportunity to give back to the game he grew up playing.
"It's one of the things that our school and our kids take a lot of pride in -- working with the younger kids," Jaffe said. "It really shows our guys where they came from. They had a chance to go to stuff like this when they were younger and they had a chance to work with older guys that basically look like superstars out there."
As for the Harper connection, the coach said he throws that in to potentially gain young fans.
"Everybody knows who Bryce Harper is," Jaffe said with a laugh.
For clinic-goers, it was an opportunity to interact with the next wave of JUCO World Series stars and hone baseball skills. There were two stations for pitching, a station for catching, several fielding stations, a baserunning station and two more covering batting skills.
Kids slid on the outfield grass, dove for ground balls in the dirt and took big swings at foam baseballs, spraying them around the stadium. Hitting was a favorite, but for many youngsters the biggest highlight was meeting JUCO World Series players.
Luke Weaver, an 11-year-old from Fruita, Colo., said he "likes hitting the ball really far," before adding that he appreciates the extra coaching.
"It's kinda cool to just meet the players and for them to show us how to play properly," Weaver said.
Steven Liman, an 11-year-old from Grand Junction, echoed his friend, saying that meeting the players and "just playing baseball" were the best parts of the clinic.
Josh Zotto, another 11-year-old from Grand Junction, said working with JUCO World Series players helps with his hitting.
"It just helps me work on it," he said.
Youngsters from all over Colorado -- and even a few players from Utah -- participated in the clinic and received a T-shirt, plus a padded bat and ball. Many players were mobbed for autographs after the clinic and a few kids just wanted to talk baseball.
Jacob Charron, a Canadian catcher for Crowder College (Missouri), said the attention from fans is nice and giving back is even better.
"It's a lot of fun to teach these kids a little bit of what we do every day and it kinda brings you back," Charron said. "It makes you feel like a kid again and makes you realize how much fun baseball really is. It helps you appreciate it."