Whether the reasons are physical, mechanical or mental, for many hitters, power is something that develops later in their careers.
The primary driver behind players seeing their power spike is an increase in strength. High school players drafted at 18 and international free agents signed at 16 add weight to their frames, get stronger and develop more force to drive the ball.
Sometimes a player's power increase is more mechanical. Changing a hitter's swing plane, getting his lower half more involved in his swing, adjusting the way he sets up, loads or uses his hips can all make a difference toward a player's ability to hit the ball with authority in games.
Other times, it's more about a player maturing as a hitter. A hitter who improves his plate discipline is going to put himself into more advantageous counts and get himself better pitches to hit. Learning which pitches to turn on and gaining a better understanding of how pitchers are attacking them to be able to anticipate what's coming helps a player become a better hitter overall and can lead to more extra-base thump.
While players like Chris Davis and Kris Bryant were always known for their power as prospects and projected to be 30-plus home run threats, other players who projected to have moderate power when they were in the minors have developed surprising sock as major leaguers. These seven players have all surpassed the power projections forecasted for them when they were prospects.
1. Mookie Betts, of, Red Sox
I may have been driving the Mookie Betts bandwagon since he was in the lower minors. Betts had a sound swing and terrific hand-eye coordination that led to supreme bat control, with the plate discipline and above-average speed to make him an on-base machine and ideal leadoff hitter in the future.
But there's no way I would have expected the 5-foot-9 Betts to hit 30 home runs, especially when he's still just 23. In 2012, the year after he was drafted, Betts hit zero home runs in 71 games with short-season Lowell. He did hit 15 home runs the next season, and it looked like Betts had a chance to develop into someone who could hit 15-20 home runs during his prime. Instead, Betts has developed into one of the most dangerous sluggers in the game, even if he doesn't look like one, with 30 home runs and a .313/.355/.546 line in 140 games.
2. Brian Dozier, 2b, Twins
Safe to say the Twins have received a good return on their $30,000 investment to sign Dozier as an eighth-round pick out of Southern Mississippi in 2009. As a 24-year-old in 2011, Dozier's final full season in the minors, he hit nine home runs in 127 games between high Class A Fort Myers and Double-A New Britain. Dozier stood out for his plate discipline and bat control—he had nearly as many walks (154) as strikeouts (184) during his minor league career—but some scouts weren't sure he would ever crack double-digit home runs.
After learning to better incorporate his lower half into his swing, Dozier has safely crushed those projections and did it as more than just a one-year fluke. After hitting 23 home runs in 2014 and 28 last year, Dozier is second in the majors with 40 homers, including 26 in his last 56 games.
3. Rougned Odor, 2b, Rangers
Odor never stood out for any of his tools. He never had great speed. His arm strength and fielding were always better suited for second base than shortstop. And while he had some sneaky pop, he never projected to hit for big power, especially when he signed as a skinny, 5-foot-9 kid out of Venezuela at age 16.
What Odor could always do—whether it was at international tournaments or anywhere else he went on his quick rise through the minors—was hit. Odor has a sweet lefty swing, and as he's increased his strength, his power has spiked. Once expected to top out in the 15-20 home run range, Odor is still 22 and already has hit 31 home runs this season. Some of that has come from Odor selling out for power at the expense of contact, which has caused his OBP and overall value to sink. There is plenty of time for Odor to find the optimal approach to balance contact and power, at which point he should become one of the best overall players in baseball.
4. Brad Miller, ss/1b, Rays
Scouting reports on Miller during his minor league days praised his hand-eye coordination, plate discipline and line-drive stroke. From Miller's scouting report in the 2012 Prospect Handbook: “He uses a contact-oriented approach, letting his hands work and shooting balls from gap to gap. He hits towering home runs in batting practice and could have close to average power."
Now 26, Miller has figured out how to translate that raw power into the games and exceed even the loftiest projections for his future power. He's hitting .249/.305/.494 this seasons, with his 28 home the most among major league shortstops, although the last month he's been playing primarily first base.
5. Jose Altuve, 2b, Astros
I don't think any scout in Venezuela looked at the 16-year-old, 5-foot-6 Altuve and thought, “Here's a future 20-25 home run hitter." In his first three pro seasons, Altuve hit five home runs in 170 minor league games. Even internally, some in the Astros organization considered him an organizational player. Yet Altuve has surpassed everyone's expectations for him, not only becoming one of the best pure hitters in baseball, but a player who has put himself in the MVP conversation because of a power spike this season, batting .337/.398/.543 with 23 home runs in 143 games.
6. Eugenio Suarez, 3b, Reds
Tigers international scouts have a knack for sneaking out of Venezuela with overlooked players who develop into good prospects and sneaky-good big leaguers. Hernan Perez has become a productive contributor at a variety of positions with the Brewers, while Suarez has been a steady regular for the Reds at third base.
As a prospect, Suarez was a shortstop with a short, flat swing who stayed inside the ball and worked gap to gap with below-average power. Suarez's value figured to come from his ability to play in the middle of the diamond, put the ball in play and work the count well enough to get on base, with perhaps enough power to grow into 8-12 home runs. While Suarez's strikeout rate increased this year, so has his power, with 20 home runs and a .255/.321/.428 line in 139 games.
7. Freddy Galvis, ss, Phillies
When you're one of the worst teams in baseball, you can afford to have Galvis be your starting shortstop. Galvis is a poor overall offensive player, hitting .236/.270/.397 in 557 plate appearances, but he is demonstrating more game power than he was ever anticipated to have. A slick-fielding, light-hitting shortstop as a prospect, Galvis still isn't much of a hitter, but he is doing more damage on contact than ever before, with 18 home runs twice as many as he's ever hit in another season.