For a team so well-versed in analytics, yet dismissive of launch angle as an end-all-be-all offensive solution, the fact that Diaz spent 2018 mostly in limbo between minor league depth and part-time player was confusing and frustrating and upsetting.
As a batter, Diaz has an uncanny ability to hit the ball hard as hell. As outlined by Tom Tango, balls hit with an exit velocity above 95 mph have a wOBA above league average. Which is to say, hitting the ball hard produces good results. No kidding.
In a limited sample (90 batted balls) in 2018, 44 percent of Diaz’s hits left the bat at 95 mph or greater. Tango rates an average player as someone who accomplishes that feat 35 percent, whereas a top player does so 50 percent of the time. Thus, of the 6,300 plate appearances given to batters this year, the Indians chose to give a player with well above-average exit velocity (and, logically, wOBA) a chance just 1.2 percent of the time.
If that was not aggravating enough, consider Diaz’s ranking among all MLB players (minimum of 90 batted balls, 406 qualifiers): 135th in maximum exit velocity (111.6), 22nd in average exit velocity (92.1), and 52nd in hard hit percentage (44.4). Among Indians players in those same categories, Diaz ranked sixth, first, and first, respectively.
Pause for a moment to let that sink in. Diaz hit the ball, on average, harder than any other Cleveland batter and he did it more often. But he was only given 120 at-bats in the regular season and three in the postseason. It’s beyond belief.
Of course, the issue with Diaz was never how hard he could strike the ball, he’s always smacked the ball with authority. His issues stemmed from the direction the ball went upon being struck, because hitting a ball at 111 mph in the dirt in front of home plate will more than likely result in an out. However, while Diaz’s average launch angle in 2017 was 0.0 degrees (122 batted balls), it increased this year to 4.4 degrees. This is not the makings of air ball revolution convert, but it was a tangible improvement, and it led to his ground ball rate decreasing from 59 to 53.3 percent, line drives increasing from 22.1 to 23.3 percent, and fly balls increasing from 8.7 to 9.5 percent.
The improvements, however slight, paid dividends, as Diaz posted a slash line of .312/.375/.422, with 15 runs scored, 15 RBI, and eight extra-base hits, including his first home run. Diaz rated as an above-average hitter by OPS+ and wRC+ (both 115), offering some proof that a low average launch angle is not a death sentence offensively.
He wasn’t the only one to offer a counterpoint to launch angle evangelists. With an average launch angle of 4.7 degrees and average exit velocity of 92.3 mph, Christian Yelich put together an MVP-worthy season this year without sending every ball toward the Milwaukee sky. Of course, Diaz is not Yelich and comparing players apples-to-apples is a fool’s errand, but the Indians have an office full of smart folks who understand that launch angle alone is no determinant of success (which was true before Yelich’s breakout, too).
Unfortunately, that makes wondering what might have happened were Diaz given the more time to develop as a hitter at the big league level more frustrating. Since 2015, Yelich’s launch angle has increased from 0 to 2.5 from 2015 to ‘16 and to 4.7 each of the last two seasons; accordingly, his barrel percentage rose from 4.8 to 9.7 from ‘15 to ‘16 and 12.9 this year. Diaz barreled the ball considerably less often, 4.4 percent, but even that was an increase from his 2017 rate of 3.3 percent
If Diaz mirrors Yelich even a little bit, more playing time could be the key to unlocking his full potential. Which gets right to the heart of what the #freeyandy Twitter mob has been ranting about for years now: It is in the Tribe’s best interests to make room for a talent like Yandy to develop at the major league level. Sure, Diaz is no Josh Donaldson (particularly on defense), but the Tribe’s willingness to move Jason Kipnis for the rain-bringer is proof-positive Yandy could have played more often this year.
In 2019, the Indians have a choice to make: give Diaz a job that is his to lose or move him to a team that will give him that opportunity. According to Terry Pluto, the organization is finally “prepared to give him a chance as a regular.” But if they are not, you can be sure a majority of teams would be willing to find a home for Yandy’s skill set. The Cubs, for instance, gave that opportunity in 2018 to David Bote, who profiles a lot like Diaz (3.5 degree launch angle, 93.5 mpg exit velocity, 52.8 hard-hit percentage) and may just be the third baseman of the future in Chicago.
Much of Diaz’s future could hinge upon Kipnis’ status for 2019 or who has more trade value left between the two. It would be a shame to see Diaz leave Cleveland and become the next Jesus Aguilar, but at this point the team would be hurting itself and the player by not giving Yandy an extended chance — as an Indian or in someone else’s infield.