Brett Ballantini interviewed Diamondbacks GM Dave Stewart for MLB Trade Rumors. Most of the answers were standard, like signing Zack Greinke was good and he didn’t take pleasure in taking him away from the NL West rival Dodgers or Giants, who were also interested.
The most interesting part was Stewart’s response when he was asked about reliever Tyler Clippard‘s fly ball rate. The club signed Clippard to a two-year, $12.25 million deal in February after he helped the Mets reach the World Series. Clippard is known for his high rate of fly balls, leading all qualified relievers at 60.6 percent last season, according to FanGraphs.
Here’s the question followed by Stewart’s answer:
[MLBTR] Is there concern about Clippard’s fly ball rate [79 percent in 2015], especially pitching in a park where the ball carries like Chase Field?
[Stewart] I’m not really understanding what the fly ball rate really means. A fly ball can be an infield fly, or hit to shallow center field, or make it to the warning track. You look at Tyler’s numbers last year, and even with the fly ball rate he had a nice [2.92] ERA and a good season. That’s what we’re counting on.
Stewart is right that fly ball rate, at least the one calculated by FanGraphs, includes both infield and outfield fly balls. But they also specifically calculate a pitcher’s infield fly ball rate as a percentage of total fly balls allowed. Clippard’s was 13.3 percent last season, which is about four percent above the league average and ranked 31st out of 137 qualified relievers. He is very close to being in the top quartile of relievers in that category.
Clippard’s skill in inducing weaker fly balls has certainly contributed to his success. Hitters hit for a .093 average and slugged .268 on fly balls against Clippard last season, for example. The major league average on fly balls was .151 and hitters slugged .444 on average.
Of course, it hasn’t all been good. Over the last five seasons, 108 pitchers have thrown at least 200 innings, but only one of them allowed as many home runs as Clippard (40), Ernesto Frieri. But last season, Clippard only yielded eight round-trippers out of 120 total fly balls allowed, or a 6.7 percent rate. The major league average home run rate as a percentage of fly balls was 10.8 percent. Relatively speaking, Clippard is good at both inducing fly balls and limiting home runs on those fly balls.
Stewart could have phrased his desire for nuance better — upon first read, I thought he didn’t understand the concept — but he is right to make a distinction between fly balls that are hit hard and fly balls that are not. It is worth wondering though if Clippard, who threw in the pitcher-friendly O.co Coliseum and Citi Field last season, might give up more home runs than expected at the hitter-friendly Chase Field.