Then there's De Leon, who was listed as the No. 27 prospect by MLB.com during the 2013 international signing period. The switch-hitter signed with the Rangers for $550,000, and he impressed his new organization by being one of the youngest players in the South Atlantic League last season.
De Leon played in one game for Double-A Frisco when the Rangers had a vacancy there last season, and he batted .244 with 42 runs in 85 games for Class A Hickory in the South Atlantic League. And then, instead of flying home for the winter, De Leon headed for instructional league and the AFL.
It's enough to fatigue even the most conditioned athlete, but De Leon is loving the experience.
"I'm out here having fun and I'm trying to learn every day," said De Leon via interpreter and teammate Deven Marrero. "I'm trying to get some knowledge from the older guys. I'm young and I have a lot to learn in this game. I'm out here learning every day, working hard and picking everybody's brain."
Marrero, born in 1990, was still in high school when he was De Leon's age, but he went on to star at Arizona State University before signing with the Red Sox as a first-round draftee. And he's fairly typical of an AFL player. Two players on the Surprise Saguaros -- Ryan Dennick and Rusney Castillo -- were born in 1987, and just seven players on the roster are even within five years of De Leon's age.
But if the youngster's age is an outlier, his skill level fits right in with his more experienced peers. Delino DeShields, manager of the Saguaros, was second in the National League's Rookie of the Year balloting as a 21-year-old, and he said he's liked what he's seen from De Leon thus far.
"He's a baby, but he's holding his own," said DeShields of his shortstop's skill level. "He's got great actions and the kid's not lacking confidence. That's definitely going to help him going forward. But with him being so young, I'm just surprised at how advanced he is right now. He looks young, of course, because he is a young kid. But you put him between the lines and he holds his own."
De Leon hit .176 in his first five AFL games, but he logged two hits in his first two at-bats on Monday. The 17-year-old is still learning to be comfortable with English and with ancillary parts of the game like conducting interviews, but his confidence shines through with even the most basic questions.
De Leon was asked Monday if it's intimidating to play against older competition, but he replied that he has no fear on the field. He also said that he's young and doesn't get tired when asked about the length of his season, and he said he speaks with his family back home almost every day.
But here he is, far from home, playing against men who have had time to learn their craft. De Leon said that he never expected to be here but that he's enjoying every minute of the experience.
"I'm just out there and just playing," said De Leon. "I never thought I'd get the opportunity, but when I did, I just took advantage of it. I ran with it and I had fun with it and I played very well."
DeShields, a former second baseman and outfielder, played 13 seasons in the big leagues and finished his career with more than 1,500 hits. He works in the Reds' organization during the regular season and has only had De Leon for a few weeks, but he's impressed with what he's seen.
"Just grow," said DeShields of De Leon's future. "He needs to grow from a maturity standpoint and get stronger. All the skill is there. He just needs to get stronger and grow mentally within the game."
At this point, that seems inevitable. De Leon, 6-foot-1 and listed at a wiry 160 pounds, has so much room to grow into his frame and so much time to do it. One day, he may look at his time in the AFL -- and his record for being the league's youngest player -- as a springboard to bigger things.
"I feel awesome about it. It's always good to be that first guy and I just want to work hard," he said. "That's all I want to do: Work hard and prove to these other guys that I can play and I belong here."