Hype has long followed the right-handed Kaprielian, even as he continues to rehab from Tommy John surgery. Fowler was also part of a touted group of Baby Bombers prospects, while Mateo for some time reigned as the top Yankees prospect. Then the struggles came, and a two-week suspension for violating team policy, and Mateo seemingly fell out of favor while another shortstop, Gleyber Torres, took over the No. 1 spot.
Now Mateo finds himself in a new organization -- he's ranked by MLBPipeline.com as the A's No. 4 prospect -- and is proving himself still to be an elite prospect.
The shortstop position in Oakland is occupied by Marcus Semien, who is under club control through 2020, but Semien's long-term future with the club is uncertain, allowing Mateo time to potentially force his way into the big league picture.
Only middle infielder Franklin Barreto, left-hander A.J. Puk and Fowler rank higher on the A's prospect list than Mateo, who could also be considered an outfield option down the line.
"I think you keep him at short for a while," A's manager Bob Melvin said. "You look as the closer he gets here, is there a need somewhere else? He's probably athletic enough to play anywhere. I think [the front office] is happy with what they saw at shortstop.
"Really, the athleticism in the organization picks up with guys like him and Fowler and certainly [Matt] Chapman and guys like that."
All eyes have been on Mateo since he signed out of the Dominican Republic in 2012, his value seen through his excellent speed and versatility in the field, with a cannon of an arm.
There have been questions about his bat, but Mateo made a good first impression at the plate upon joining the A's system, hitting .292 with four home runs, 16 extra-base hits and 20 RBIs in 30 games for Double-A Midland. He has 234 stolen bases in 452 Minor League games.
The A's expect Mateo, who is still just 22, to begin the 2018 season at Triple-A Nashville. He is currently clocking time for Toros del Este of the Dominican Winter League, where he has three homers and 10 stolen bases in 17 games while slashing .260/.270/.425.
• A's offseason leagues stats
"He took a huge leap forward this year, just moving from A ball to Double-A," A's general manager David Forst said. "Mateo has a ton of talent and a really high ceiling.
"We're excited about Mateo as one of the guys we're looking forward to seeing in spring next year. We'll see how quickly he moves up."