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Miami Marlins analysis: Why is Jacob Turner struggling?

Miami Marlins starter Jacob Turner is suffering from an elemental problem that his rotation peers have seemingly resolved. That alone seems to separate him from the rest of the team in their success on the mound.

Marc Serota

The Miami Marlins have quietly put together a solid starting rotation despite one of the worst offenses of this era. Miami has a staff ace in Jose Fernandez and a trio of solid options behind him in Nathan Eovaldi, Henderson Alvarez, and Jacob Turner. The Marlins were looking to all three of these guys to take steps towards becoming efficient Major League starters, and thus far at least one of them (Eovaldi) has made significant strides this year.

Of the three, however, the only one who has appeared to take a step back this season is Turner. Despite a shiny 3.13 ERA, Turner's performance in 103 1/3 innings this year has been disappointing. His 4.08 FIP shows a pitcher who is closer to just average, and the 4.68 xFIP and 4.93 SIERA indicate a poor pitcher who may have benefited from plenty of good luck on home runs.

In looking for the areas of concern for Turner, one weakness seems to be increasingly sticking out: his surprising lack of control. Earlier this year, the lack of strike zone control was "effectively wild," as it appeared Turner was morphing into a pitcher who threw out of the zone often to get swings and misses. Now, those swings and misses are down as hitters are failing to chase his pitches, and the most recent results have been ugly. In the month of August, Turner managed a 4.18 ERA, but that was backed by a 5.79 FIP and more walks (21) than strikeouts (16).

A decent indicator of his lack of control appears to be his zone percentage from this season, and this is where he stands out compared to the other Marlins starters.

Marlins pitcher, 2013 Zone% BB%
Nathan Eovadli 55.7 9.0
Jose Fernandez 54.7 8.4
Henderson Alvarez 52.6 6.2
Tom Koehler 51.7 9.3
Jacob Turner 45.7 10.4

It is not a clear-cut correlation, but it is no surprise that the Marlins starter with the least pitches thrown in the strike zone has the highest walk rate. Guys like Henderson Alvarez may be taking advantage of contact in avoiding walks, but in the case of Turner, he simply cannot place pitches in the strike zone, and that has become an issue. It has not helped that players are also increasingly not swinging at those pitches; while his overall season's swing rate on pitches out of the zone is up from last season to 31 percent, it has been down to 27.5 percent in the second half as hitters adjust to that wildness.

How important is that wildness? It may seem obvious, but pitchers who are more often in the strike zone tend to be more successful than those who are not. Among qualified starting pitchers in 2013, Turner's 45.7 percent mark would have rated the ninth-worst in baseball were he qualified. If you look at the list of the ten lowest zone percentages among qualified players, four of those pitchers have ERAs currently over 4.00, and four have FIPs over 4.00 as well. The overall raw average for ERA in that group is 3.86, while the FIP is 3.99.

What about the opposite end of the spectrum? The ten best zone percentages in baseball has a cavalcade of good players on the list, including Miami's own Fernandez. Of those ten best pitchers in hitting the strike zone, only one (Phil Hughes) has an ERA over 4.00, and two (Hughes, Bronson Arroyo) have a FIP at 4.00 or above. Overall, their group raw average for ERA is 3.31, while their FIP is 3.52.

Again, it should not surprise anyone that being in the strike zone more often makes you a more successful pitcher. The Marlins have a trio of starters who were in the zone as much as possible, and for each of those guys, that game fits them well. Fernandez's stuff is untouchable, so being in the strike zone is relatively safe. Nathan Eovaldi could claim the same thing, at least with his fastball, as it has been one of the most effective pitches in the game. Alvarez needs to pound the strike zone because he depends on ground balls to succeed.

Does Turner's game fit well into this category? He previously had the reputation of a "control pitcher" in the minors with great polish, but so far he has not thrived in that department. He also has never gotten a lot of strikeouts in the minors or majors, so it is difficult for him to get away with poor control and high walk rates. Clearly the second half adjustment by hitters tells us that Turner is unlikely to survive the majors with this approach, so he will have to pound the strike zone more to be successful. Whether he can do this after two years of erratic throwing remains to be seen.

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