Stats say: These 10 prospects should take off in '19

December 18th, 2018

One great feature on MLB Pipeline is the prospect stats tool. In addition to offering helpful data on specific performances through all the basic, commonly-used stats, it's become an especially valuable resource for doing deeper dives into players' strengths and weaknesses.
Specifically, the 'Advanced search' tool allows for a highly detailed and customizable look inside specific players' performances and how they compare to others throughout both the Minors and big leagues.
So, with the offseason now in full swing, we thought that we'd begin a new series using the aforementioned stats tool to take a deeper dive into certain players' 2018 seasons as a means of forecasting future success.
The goal in this first installment is to identify hitters who have the potential to make developmental strides in 2019. That could mean a full-blown breakout campaign for some players, while for others it could simply mean a return to form after a down year.
In the Minor Leagues, distinguishing types of contact is not a perfect science -- for example, some official scorers might label a line drive as a fly ball and vice versa. So, for the sake of consistency, we'll mostly be looking at line-drive and fly-ball rates, or a combination of the two, for this article. Pop-ups are not factored into the fly-ball rates, and please keep in mind that these numbers represent raw data and have not been properly adjusted for league and/or park factors.
Luis Carpio, 2B/SS, Mets' No. 17
Carpio's .219 average was the fifth worst among qualified hitters in the Class A Advanced Florida State League last season. He did, however, hit a career-high 12 homers and 21 doubles in the pitcher-friendly league, and there are quite a few signs that the 21-year-old is in store for more success moving forward. Specifically, Carpio had a surprisingly low .242 batting average on balls in play last season even though 52.2 percent of his contact was either a fly ball or line drive. He also struck out a reasonable 18.4 percent clip, had an equally reasonable 9.4 percent swinging-strike rate and walked 9.3 percent of the time.
Yu Chang, SS/3B, Indians' No. 6
Chang had a solid first Triple-A campaign by all standards, slashing over .256/.330/.441 over 127 games in the International League at age 22. And while he's never really hit for a high average as a .251 hitter in more than 500 Minor League games, Chang has long shown that he can drive the baseball to all fields using a combination of plus bat speed, top-hand-led barrel control and a swing that features good extension through contact. Last season, 57.6 percent of Chang's contact was a line drive or fly ball, a mark that ranked tied for second among all Top 30 prospects (with at least 300 BIP) and furthered a trend that's followed him during his rise through the Minors.

, 2B/SS, Marlins' No. 9
After joining the Marlins in the offseason blockbuster that sent to Milwaukee, Diaz totaled 13 home runs, 41 extra-base hits and produced a .232/.340/.399 line over 119 games between Double-A and Triple-A. While Diaz's ability to drive the ball out of the park to all fields remains one of his strengths, his fly-ball rate has hovered around 29 percent in the past two seasons -- well below the 39.7 percent mark he posted back in 2016, when he connected on a career-high 20 home runs. The good news is that the 22-year-old's plate discipline as well as his feel for using the entire field has remained steady during his rise through the Minors, so the ingredients seemingly are there for Diaz to make strides offensively in 2019.

Jeter Downs, SS/2B, Reds' No. 7
The 2017 Competitive Balance A pick (No. 32 overall) showed a serious knack for lifting the ball in his first full season en route to 13 home runs and 23 doubles. His 33.2 percent fly ball rate was the 10th-highest among Top 30 prospects who had at least 350 BIP in 2018, and he also posted a solid line-drive rate of 17.5 percent. The fact that he has some swing and miss to his game (19.7% K%) and hits a lot of popups (16.6 percent) highlights Downs' room for growth, so improvement in those departments could very well prompt an uptick in power from the 20-year-old middle infielder.

Lucas Erceg, 3B, Brewers' No. 4
At face value, Erceg underwhelmed in his first Double-A campaign by hitting .248/.306/.382 with 13 home runs over 508 plate appearances. His strikeout and walk rates both improved, though, and he even drove the ball in the air more frequently compared to his first full season. The left-handed hitter's combined line drive-fly ball rate of 54.1 percent was 10th-best among Top 30s with at least 350 BIPs and suggests that the quality of his contact might translate well in the Majors even if the results currently aren't there, and there are some evaluators who believe Erceg will earnestly tap into his plus raw power as he learns to turn on the ball.

Santiago Espinal, IF, Blue Jays' No. 23
Toronto acquired Espinal from the Red Sox for Steve Pearce back in June, in the middle of the 24-year-old infielder's breakout campaign. He would ultimately hit .297/.356/.444 with 43 extra-base hits including 10 home runs over 124 games, finishing the year in Double-A. Espinal produced a line drive or fly ball in 44.4 percent of his 518 plate appearances in 2018, and that number was the highest among qualified Top 30 prospects. 56.7% of his BIP was either a line drive or fly ball, the second-best among Top 30 prospects with at least 350 BIP, yet his .412 average on such contact was the 10th-lowest mark. Factor in his solid strikeout and walk rates (12.9 and 7.3 percent, respectively) and the fact that he uses the entire field well, and a case can be made that Espinal is merely scratching the surface of his underrated potential.

, C, Tigers' No. 12
Few hitters elevated the ball last season better than Rogers, who hit a line drive or fly ball nearly 60 percent (59.8) of the time when he put the ball in play That translated to 17 homers over 99 games in his first Double-A season, though it came at the cost of a .219 average and a career-worst 27.5 percent strikeout rate. Making more contact should result in even more over-the-fence power in future seasons for the 23-year-old, and along with his plus defense, gives him a realistic floor as an everyday big league catcher in the mold of Mike Zunino.

Brent Rooker, 1B/OF, Twins' No. 7
Productive first baseman in the Minors are all too often overlooked, if only because so many prove to be Quad-A types or ultimately have to take a back seat to an even more productive incumbent. But a deeper dive into Rooker's 2018 campaign suggests reason to be bullish on his future. The Twins' Competitive Balance Round A pick from the 2017 Draft moved up to Double-A for his first full season and finished second in the Southern League in home runs (22) and tied for first in doubles (32). Specifically, 56.6 percent of Rooker's batted balls were line drives or fly balls -- third-best among Top 30s with at least 350 BIP -- and 14.8 percent of those were extra-base hits

Keibert Ruiz, C, Dodgers' No. 2
As MLB Pipeline's No. 39 overall prospect, Ruiz is perhaps the most notable name on this list. He proved to be a highly advanced hitter as a 19-year-old in Double-A last season, slashing .268/.328/.401 with 12 homers over 101 games. Hitting from a pronounced crouch, Ruiz is adept at using his lower half and quick bat to drive the baseball, and nearly half (49 percent, to be exact) of his contact was either a line drive or fly ball in 2018. Of course, that means Ruiz also had a high ground-ball rate (44.7 percent). However, given his present strengths as a hitter at such a young age, along with fact that he makes a lot of contact, there's reason to believe Ruiz will be an even more impactful hitter, hitting for both average and power, as he learns to elevate the ball more consistently.

, 2B, Cardinals' No. 11
After hitting .324 across his first three pro seasons, Schrock uncharacteristically slashed just .249/.296/.331 last year over 114 games in the hitter-friendly Pacific Coast League. While some of Schrock's struggles can be attributed to poor luck (.260 BABIP), he did experience a dip in his line-drive rate (from 23.1 percent to 19.0) and employed a more pull-heavy approach after he had excelled at using the entire field in previous years. Beyond that, however, Schrock once again posted strong strikeout and walk rates, rarely swung and missed (4.3 percent whiff rate) and hit the ball in the air more often. So don't be surprised if the 24-year-old returns to his pre-2018 form in '19.