5 hitters who could be hidden gems in 2019

Much of the offseason discussion centers around which players teams can add to improve their roster, but sometimes the answers can lie within a team's own depth chart.
Players like Brandon Nimmo, José Peraza and Johan Camargo became big contributors in 2018 as they took advantage of more playing time. Sometimes, all it takes for a youngster or ancillary roster piece to break out is simply an opportunity.
With that in mind, here are five players whose mix of promising Statcast™ metrics and opportunities for major playing time could translate to big seasons in 2019:
Chad Pinder, UTIL, Athletics
Fans might recognize Pinder as the A's do-it-all utility man who's logged games at seven different positions over parts of three seasons. That versatility off the bench is valuable enough (Pinder registered 2.2 WAR in 2018, per Baseball-Reference, despite starting just 43 games), but there could still be plenty more to unlock in Pinder's bat. Statcast™ will soon release its "batter similarity scores" on its Baseball Savant player pages using a combination of walks, strikeouts and quality of contact, and look who showed up as a comparable to Angels star Shohei Ohtani:

Using those same factors, Pinder's own comparables include such humble company as Ronald Acuña Jr., Paul Goldschmidt and Justin Upton. That's because while Pinder's game does feature some swing and miss, it also features a whole lot of effective launch. Pinder made hard contact (or exit velocities of at least 95 mph) 42.5 percent of the time last season, putting him roughly in MLB's top 20 percent, and barreled 14.2 percent of those balls -- 12th-best among 281 hitters who put at least 200 balls in play. Hitting barrels are the best thing a hitter can do at the plate, and Pinder did so at essentially the same rate as American League MVP Mookie Betts.
Pinder's explosive contact paired with his league-average walk rate landed him an expected weighted on-base average (xwOBA, Statcast™'s all-purpose metric based on those tenants of contact, walks and strikeouts) of .364 in 2018, right in the neighborhood of Acuna, Juan Soto, Aaron Hicks and Jesús Aguilar. He'll have to win the A's left-field job over Mark Canha, Dustin Fowler and Nick Martini in Spring Training, but there's a lot of potential for Pinder to boost a lineup that was already baseball's fourth-highest scoring offense a season ago.
Luke Voit, 1B, Yankees
Voit certainly won't keep up the insane .333/.405/.689 slash line he put up over two months in the Bronx, but it's also hard to ignore the underlying peripherals that fueled his numbers. Looking at Voit's entire 2018 season with St. Louis and New York, he doubled his '17 walk rate to finish two points better than the average Major Leaguer, cut his ground-ball rate dramatically and pulled the ball more to left field while keeping his strikeout rate at an acceptable 26.7 percent.

And then there was Voit's eye-catching power. The Missouri native finished with an even 100 balls put in play last season, and while that's an admittedly small sample size, here's where he wound up among 390 MLB hitters when we set those 100 BIP as a minimum:
Avg. exit velocity: 93.0 mph (tied for ninth-best)
Hard-hit rate: 54.0 percent (third)
Barrels/plate appearance: 12.4 percent (first)
xwOBA: .441 (first)

Those numbers are either "elite" or "random," depending on whether you think Voit could sustain that production over 500 plate appearances. But the Yankees have sat out on potential Hot Stove first-base like Goldschmidt, Matt Adams, Steve Pearce and Daniel Murphy, and Greg Bird's stock is at an all-time low. So, it appears New York is at least willing to wait and see if Voit can truly be a full-time player. If he replicates even a modicum of his white-hot stretch last summer, the Bronx Bombers' lineup instantly gets even scarier.
Daniel Vogelbach, 1B/DH, Mariners
Vogelbach's 6-foot, 250-pound frame makes him an easy player to root for, and this stocky slugger has already shown he can put some serious torque into a baseball.

Vogelbach didn't light up the stat sheet with his .207/.324/.368 performance over 102 plate appearances last season, but there were encouraging signs -- most notably his 52.5 percent hard-hit rate and 11.5 percent barrel rate. Even beyond power, Vogelbach posted above-average marks in walk rate (12.7 percent), whiff-per-swing rate (23.6 percent) and chase rate (18.8 percent). He's routinely been a high on-base hitter in the Minors, and the plate discipline he displayed in 2018 signals he could still put it all together with more playing time.
Opportunity is the biggest roadblock for Vogelbach, but Seattle's rebuild could open things up. MLB.com's Jon Morosi reported Friday that the Mariners are "increasingly confident" that they will trade designated hitter Edwin Encarnación before Opening Day, and first baseman Ryon Healy (-0.6 WAR) struggled in his Seattle debut. Look for general manager Jerry Dipoto and manager Scott Servais to give Vogelbach at least one more look to see if they he's a slugger they can retain for the Mariners' next competitive window.
Ji-Man Choi, 1B/DH, Rays
Choi has had a hard time sticking with one club over his first three seasons, but after Tampa Bay designated C.J. Cron, traded Jake Bauers and missed out on free agent Nelson Cruz, the Korean-born slugger is the current front-runner for the Rays' DH spot. Tampa Bay has already made a ton of roster moves, but perhaps the club is signaling it believes in Choi's power by keeping him around.

There's a lot to like with Choi, including his 12-percent career walk rate and above-average 20 percent chase rate. Though he only put 148 balls in play over the last two seasons, Choi barreled 12.2 percent of them and owns a .469 expected slugging percentage in that span. That would be solid production in 2019, and -- even better for the small-market Rays -- it would be cheap production, since Choi won't be arbitration-eligible until at least 2021. Tampa Bay didn't get Cruz, but perhaps it already has a cost-effective alternative.
Ryan O'Hearn, 1B, Royals
O'Hearn was one of the few bright spots in the Royals' tepid lineup as he compiled a .950 OPS and 12 homers over just 170 plate appearances last season. The Texan racked up his fair share of whiffs, but he still got on base at a 35-percent clip. And when O'Hearn did connect, it was often loud: The rookie finished with a hard-hit rate (44.2 percent), average exit velocity (91.4 mph) and barrel rate (12.5 percent) that were all within the top 15 percent of those 390 hitters who put 100 balls in play.
O'Hearn sits atop the Royals' depth chart at first base, and it seems unlikely that Kansas City signs a free agent at that position as it continues to foster its younger talent. That should give O'Hearn plenty of time to see if he can maintain that power over a full campaign.