Despite spending last season with the Miami Marlins, starter Tom Koehler had to battle for the fifth spot in the rotation. With a solid spring, Koehler won the job, and after starting the year 2-1, has attributed his success to having better command of his fastball.
Koehler has posted a 1.89 ERA to complement a 3.97 FIP in three starts. 56.4% of his 2013 pitches were fastballs, many of which were hit hard, leading to a 4.41 ERA in 23 starts.
In 2013, opposing teams feasted on the pitch. According to Brooks Baseball PITCHf/x, they went 72-for-202 (.356) on fastballs in the zone. Even on fastballs Koehler threw out of the zone opponents went 24-for-79 (.303).
Koehler thus far in 2014 has complemented Miami's other starters well. Jose Fernandez, Nathan Eovaldi, Henderson Alvarez, and now Kevin Slowey have all, with a few exceptions, had early success on the mound, and an improved offense has lead to the Marlins being five wins away from the total number of wins the squad had in April and May combined last season.
In terms of his pitch selection, Koehler's velocity has little to do with the contact made. His average fastball heading into Monday night's start is 92.7 mph, precisely what it was in 2013, and when he missed with the fastball in 2013, it was a fastball up in the stirke zone. Koehler often times has missed low in the zone throughout his last few starts.
Taking into account a much smaller sample size, so far the results are markedly different. Opponents are 7-for-31 (.226) on Koehler fastballs in the zone and 2-for-10 (.200) on fastballs out of the zone.
Should the Marlins continue to rely on their pitching to keep them in games, Koehler will be an essential part of the rotation. Miami has struggled in the past to find a consistent fifth starter, however Koehler has proven that he has the potential to fill the void.
When hitters are facing Koehler, they aren't hitting balls hard, and in his one loss, he gave up two runs to the Nationals in six innings.
Coming up in Miami's minor league system, Koehler was described as a ground ball pitcher. In 2012, 48.8% of contact resulted in a ground ball, and that number has consistently been increasing.
Overall, Koehler's ground ball rate is up from 47.6 percent to 49.1 percent, his line drive rate is down from 22.0 percent to 16.4 percent and his left on base rate has increased from 70.8 percent to 86.7 percent.
Another number that jumps out is opponents' .214 batting average on balls in play. That's 75 points lower than 2013 and likely unsustainable.
Koehler, when compared with Brad Hand, Kevin Slowey, and a pair of prospects that needed more minor league time, rightfully deserved the fifth rotation spot. He has kept the Marlins in every game he has started, and Miami has provided him with adequate run support, which he didn't receive after going 5-10 last year.