For as much as we pore over prospect rankings and Draft previews, sometimes a late-bloomer still comes back to surprise us years later. Few could have predicted in, say, 2015 that Jose Ramirez would become one of the 10 best players in baseball. Whit Merrifield didn't break out until his age-28 season with the Royals, who just rewarded him with a four-year extension.

Picking the next Ramirez or Merrifield brings up the old needle-in-a-haystack analogy, but with a look at players in the latter half of their 20s with some service time under their belts, we'll take our best shot. Here are five hitters who are logical candidates to be the next big late bloomer.

Max Kepler, OF, Twins
Minnesota extended Kepler, a Super Two player, through his four arbitration years and also his first year of free agency (and possibly his second, if it picks up his club option), with the understanding that he could be on the verge of a breakout. The 26-year-old is already valuable with his glove (he's contributed an outstanding 32 Outs Above Average over the last three seasons), and there are encouraging signs if you look past his .224 average and 97 Weighted Runs Created Plus from last year. Kepler has shown occasional flashes of power; in 2016, he was one of just 27 players who hit a ball at least 115 mph. But as MLB.com's David Adler pointed out last week, Kepler can balance that pop with a keen eye:

That's a good list of names to be surrounded by, and the discipline showed as Kepler raised his walk rate by three percentage points from 2017, while cutting his strikeout rate by five points to a well-below league average 15.7 percent. Kepler was swinging at the right pitches, and so he might be just a few batted balls away from unlocking the power more consistently.

Chad Pinder, UTIL, A's

This isn't the first time we've brought up Pinder at MLB.com, and while his numbers haven't jumped out to this point, we can't walk away from his comparisons that include Ronald Acuna Jr., Paul Goldschmidt, Justin Upton and Shohei Ohtani (based on the all-purpose xwOBA metric from Statcast™) and his potent air-ball contact. Check out where he ranks on this list, for example:

Pinder's Air-Ball Contact Has Been Elite

(Highest Expected Slugging on Hard-Hit Batted Balls in the Air*, 2017-18)

2.014 -- Aaron Judge

1.967 -- J.D. Martinez

1.940 -- Yasiel Puig

1.937 -- Giancarlo Stanton

1.872 -- Kyle Schwarber

1.864 -- Nelson Cruz

1.858 -- Gary Sanchez

1.857 -- Pinder

1.834 -- Joey Gallo

1.829 -- Khris Davis

*Defined as 95+ mph exit velocity and a launch angle of at least eight degrees. MLB average: 1.478

Pinder will turn 27 at the end of March and faces steep competition for playing time again this year, but his versatile glove (he's started games at seven different positions in his career) should hopefully give him enough reps to let his bat shine.

Mac Williamson, OF, Giants

Last year was all set up to be a big one for this 28-year-old. Williamson was already hitting 500-foot blasts in the Minors in late 2017, and then he rebuilt his swing with instructor Doug Latta that offseason and came away with an uncanny resemblance at the plate to Justin Turner, one of Latta's other clients. Williamson just missed making the Giants' roster coming out of camp, and then tore up Triple-A to the tune of a 1.026 slugging percentage before his callup in April.

That power played in the bigs. Williamson homered in three of his first five games with San Francisco, and all three of them were hit with an exit velocity of at least 109 mph -- including a 114.2 mph tater that ranked as the Giants' hardest-hit homer since Statcast™ launched in 2015 (he also knocked a 464-foot shot for the longest Statcast-tracked homer by any San Francisco player at home). In a very small sample, Williamson displayed two things the Giants have desperately lacked from their outfielders: power at the plate and a strong arm in the field.

Giants' hardest-hit homers tracked by Statcast™ (since 2015)

114.1 mph -- Williamson, 4/20/2018
113.4 mph -- Hunter Pence, 7/21/2015
112.4 mph -- Madison Bumgarner, 4/2/2017
112.1 mph -- Bumgarner, 4/2/2017
112.0 mph -- Ryder Jones, 7/20/2018

Then came April 24, when Williamson tripped over the bullpen mound and crashed into a wall, giving him concussion symptoms that dogged him the rest of the year. He's out of options this season, so the Giants should give him a long look and a path to the roster this spring.

Hunter Dozier, 3B, Royals
The power tool is there with Dozier; his 10.6 percent barrel-per-batted ball rate ranked within the top 20 percent of full-time hitters last year, and his exit velocity topped out at 112.9 mph -- higher than some noted sluggers like Davis, Anthony Rizzo, Trevor Story and Edwin Encarnacion. The next step is closing the holes in Dozier's swing that yielded a 28.1-percent strikeout rate and .278 OBP. While Dozier doesn't have a stolen-base track record, he would possess elite speed for a third baseman should he move to that position full-time this year.

Fastest average sprint speed among third basemen, 2018
(Min. 100 opportunities)

1. 28.3 ft/sec -- Matt Chapman
2. (tie). 28.1 ft/sec -- Wil Myers, Yolmer Sanchez
3. (tie). 28.0 ft/sec -- Kris Bryant, Isiah Kiner-Falefa

Dozier: 28.6 ft/sec average in '18

MLB average sprint speed: 27.0 ft/sec

Ryan O'Hearn might have already surpassed this former first-round Draft pick in terms of excitement within the Royals' system, but Dozier should get plenty more reps in a retooling year for Kansas City.

Colin Moran, 3B, Pirates

Moran finished last year with a competent .277 average and .340 OBP, but Pittsburgh fans are probably hoping there's a little more of the power they thought they were getting from the Gerrit Cole trade. Moran, 26, was a swing changer like Williamson who finally found success in the Minors two years ago, and it's probably too early to give up on that pop (18 homers in 350 Triple-A plate appearances in 2017). Moran told MLB.com last September that he was beginning to stand further from the plate to get inside the baseball, and his .300/.373/.540 slash line that month suggest the change might have made an impact. Also encouraging was the fact that Moran was hitting as many line drives as anyone over the season's last two months:

Highest line-drive rate, beginning Aug. 1, 2019

Min. 75 balls in play

1. 41.8 percent -- Freddie Freeman

2. 38.3 percent -- Michael Brantley

3. 38.2 percent -- Tommy Pham

5 (tie). 37.1 percent -- Moran, Yan Gomes

The Bucs' lineup could use turnaround years in several spots in the lineup, including from Josh Bell at first base and new additions in right field and shortstop. Moran seems like a good candidate to do the same, and competition at third base from Jung Ho Kang should provide extra motivation.