But the reason Betts has outraced the projections with his pace of development is actually because of something that is a direct contrast to the speed that he so often displays on the bases and on defense.
Betts, you see, is able to slow the game down. Some talent evaluators from the Red Sox first noticed this about Betts when he was on the basketball court as a standout point guard for John Overton High School in Nashville, Tenn.
"He was better than just a basketball player," said Red Sox director of amateur scouting Amiel Sawdaye. "He was a really good basketball player. And he was a point guard in high school, and our area scout saw his makeup on the basketball court. Not to say that always correlates with makeup on the baseball field, but point guards have a way to sort of slow the game down a little bit, and he did that and he showed us the same skills on the baseball field."
As excited as the Red Sox were to scoop Betts up where they did -- with pick No. 172 in that 2011 First-Year Player Draft -- they didn't necessarily know quite how dynamic and well-rounded he would wind up being on the diamond.
"If we knew what type of player he was, we would have taken him in the first round," quipped Sawdaye.
It was somehow fitting that the first home run Betts struck in his Major League career was against the Cubs, the team for which Theo Epstein serves as president of baseball operations.
Epstein was in the last of his nine years as general manager for the Red Sox, his hometown team, when Betts was selected.
"Mookie was a multisport kid in high school -- including being a decorated bowler -- who was intriguing initially for his athleticism and actions," Epstein wrote in an email earlier this week. "Danny Watkins, the area scout and a big advocate of Mookie's talent and character, did a great job scouting him along with the coordinator group, and Mookie seemed early on like a worthwhile investment of a bigger bonus deeper in the Draft.
"Then Mookie ended up acing some of the proprietary testing we had developed, so he became even more intriguing as a young player who combined elite hand-eye and reaction time with speed and athleticism. We moved him up to the fifth-round area, where we were just about certain to get him. Obviously, the player development guys have done a fantastic job with him, and Mookie has worked hard to fly through the system quicker than anyone imagined. He's become a dynamic two-way player with a great career ahead of him. It's a great story. Good for Mookie and good for the Sox."
When the Red Sox put together their player development projections for a given season, they base their Rookie Development Camp invitees on who they think could be on the cusp of reaching the Major Leagues. The same thought process is involved in setting up the roster for Spring Training.
Back in January, Betts wasn't at Rookie Camp. And he also was not at big league camp.
Hitting a home run at Fenway Park was not on Betts' radar during the winter and spring.
"No, I was just concerned with going to Double-A," Betts said. "That's said to be the big jump, and that was really my main concern, that was going to be my focus."
By staying focused on his immediate tasks, Betts also aced them, putting together a prolific season at the plate at Double-A and Triple-A.
"It's a quick ascent, no doubt about it," said Red Sox manager John Farrell. "Every level that he's been assigned to and challenged with, however you want to describe it, he has more than answered the call to it. I think the fact that he wasn't invited to some of those [things] means he's outpaced some of that projection, and I think the way we always view it is a player will tell you when their time has come and when they're ready and based on what he's done at every level throughout the Minor Leagues. The next challenge was here. The need is here, as is Mookie."
The last Red Sox prospect to get to the Majors within three years of being drafted out of high school was right-hander Michael Bowden, but he made just one start during the 2008 season of his first callup.
For the last Boston position player to get a callup that quickly, you'd have to go back to Michael Coleman in 1997, who wound up with a forgettable 22-game career.
While Coleman's demise was marked by attitude issues, Betts is the opposite -- containing poise that the organization would like all their players to have.
"He has a really inquisitive personality, always trying to learn, asking good questions about baseball situations or about fundamentals or different things that come up," said Red Sox director of player development Ben Crockett. "He's really a sponge for knowledge. He isn't satisfied with the status quo. Just always trying to gain more information. But at the same time, he's very open to suggestions and to learning."
At 21 years old, Betts has his whole career in front of him.
"It's hard to put a true time table on any individual guy," said Crockett. "I think certainly, in his case, the performance that he put together in both Double-A and Triple-A were pretty impressive and pretty unusual. At some point, they warranted promotion, given the opportunity that was present at the Major League level and the performance at multiple positions. We felt that was the right time."
And that's just fine with Betts, who in no way seems unnerved by the pressurized surroundings. Instead, he continues to gain comfort in the outfield, where he just started playing this season.
And Betts also looks forward to continuing the straightforward approach at the plate that has gotten him this far.
"I think just being able to put the ball in play," said Betts. "Make contact. I'm trying to keep my strikeout rate low and my walk rate high. And I'm trying to get on base."
Jackie Bradley Jr., another product of that 2011 Draft, is getting a kick out of being reunited with his former Instructional League roommate.
"He's smooth," said Bradley. "He's calm, collected, and that's the Mookie I've always known."
The way Betts' first career homer soared deep into the Monster seats wasn't necessarily the image the Red Sox had when they were scouting him all those years ago.
"I don't think anyone who scouted him in high school would tell you that they thought he would have this type of power," said Sawdaye. "How much power he ends up having in the big leagues, still, nobody knows. I think the idea that Mookie was a guy that could go out and hit and slug .500 and put up an OPS close to 1.000 was probably something that shocked a lot of people. I think that, obviously, we were excited when we saw him, what he brought to the table, but still realized he was a high school kid from Tennessee that was a little ways away."
There are no more levels for Betts to be promoted to now. He has climbed the ladder, so to speak. Now it's a matter of how he will fare against the best competition in the world.
"Mookie has certainly progressed quickly," said Crockett. "At each level, he's performed really well and showed that he's been ready to continue to be pushed. Certainly [the speed of his development] is unusual, but I think his ability to not only perform, but to do it while being moved up to new levels is a testament to his ability and his personality."