The Mets are heading into the season with Wilmer Flores penciled in at shortstop, but the team is planning to give Ruben Tejada playing time when Jon Niese is on the mound because of Niese’s ground ball rate, according to a tweet from Adam Rubin of ESPN New York yesterday, because Niese induces more ground balls than the Mets’ other starting pitchers.
First, let’s take a look at batted ball numbers over at Fangraphs to see whether or not that’s true. Here’s how each of the Mets’ top six pitchers on the depth chart fared in terms of line drives, fly balls, ground balls, and infield fly balls. The table below is sorted by ground ball rate in descending order. The rates cover the 2012 through 2014 seasons at the major league level.
|1||Zack Wheeler||20.5 %||50.0 %||29.5 %||11.9 %|
|2||Jon Niese||21.7 %||49.0 %||29.3 %||8.7 %|
|3||Matt Harvey||20.9 %||45.5 %||33.7 %||12.5 %|
|4||Jacob deGrom||23.2 %||45.4 %||31.4 %||7.8 %|
|5||Dillon Gee||19.3 %||44.9 %||35.8 %||8.2 %|
|6||Bartolo Colon||20.3 %||41.9 %||37.8 %||8.4 %|
So while Niese’s ground ball rate has been higher than four of his peers, it has not been quite as high as Zack Wheeler’s. If the Mets are to deploy Ruben Tejada over Wilmer Flores because of the difference in their abilities in the field, it would probably make sense to do so when a ground ball pitcher is on the mound. But why Niese instead of Wheeler?
Bill Petti has a spray chart tool that might shed some light on the differences between the two pitchers when it comes batted balls. Going back to the beginning of the 2010 season—which provides a much larger sample of data for Niese than Wheeler, obviously—here’s the tool’s comparison of the two.
Niese's spray chart shows a concentration of grounders to the left side of the infield, particularly between shortstop and third base. There might not be enough data to conclude that there is a significant difference between Niese and Wheeler in that regard, but playing Tejada with Niese on the mound looks reasonable.
Of course, playing Tejada when Wheeler is pitching would sound perfectly reasonable, too, but starting Tejada forty percent of the time would cut into Wilmer Flores's playing time pretty significantly. If Flores starts about 80 percent of the Mets' games, though, Tejada could enter games late for defensive purposes, especially if the Mets are using the batted ball data for their late-inning relief pitchers.
|1||Bobby Parnell||19.2 %||57.1 %||23.6 %||4.9 %|
|2||Jeurys Familia||15.3 %||55.6 %||29.1 %||5.0 %|
|3||Jenrry Mejia||19.4 %||53.9 %||26.7 %||5.5 %|
|4||Carlos Torres||20.6 %||44.9 %||34.5 %||9.1 %|
|5||Josh Edgin||15.2 %||44.2 %||40.6 %||1.1 %|
|6||Vic Black||20.7 %||40.0 %||39.3 %||12.3 %|