St. Louis Cardinals: A Look at Kevin Siegrist’s Development

Jasen Vinlove-USA TODAY Sports
Jasen Vinlove-USA TODAY Sports /
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St. Louis Cardinals
Jeff Curry-USA TODAY Sports /

Kevin Siegrist is less effective and more predictable against left-handed batters.

Next, I dove into Kevin Siegrist’s repertoire to examine why he is so much worse for the St. Louis Cardinals when he falls behind in the count to LHH than he is against RHH. To do this, I analyzed Siegrist’s pitch selection, fastball location, and off-speed location.

Pitch Selection

While I’ve mentioned this previously, the main explanation for the drastic difference against lefties compared to the minimal difference against righties is Siegrist’s repertoire. His change-up is by far his best off-speed pitch, but he is unable to use it against LHH. Following are Siegrist’s first- and overall pitch selections versus RHH and LHH.

St. Louis Cardinals
Source: Baseball Savant /

Against RHH, Siegrist is able to use his change-up, which is undoubtedly his best off-speed pitch. He locates the pitch extremely well, and can rely on it in any count. This leaves hitters off balance and consequently keeps him in the driver’s seat even when behind in the count to RHH.

Against LHH, Siegrist rarely uses his change-up. Instead, he features a less effective curveball, which is a noticeably worse pitch. While he has committed to using his curveball more against LHH in recent seasons, he is still more predictable when facing LHH. Additionally, a curveball is easier to recognize than a change-up, which allows hitters to stay back on the pitch more often.

Location vs. RHH

Arguably the most important factor behind Siegrist’s success against RHH is how well he executes his pitching strategy. Below, I’ve compiled the reliever’s location heat maps against righties for both his fastball and change-up:

St. Louis Cardinals
Source: Baseball Savant /
St. Louis Cardinals
Source: Baseball Savant /

Against RHH, Siegrist pounds his fastball on the inner half of the strike zone. Further, over the last two seasons, he has refined this fastball location to a tight core on the low-inside corner to RHH. The result is a pitch that limits the hitter’s ability to get his arms extended.

Additionally, this fastball location is ideal for setting up Siegrist’s change-up. This pitch is best when it fades to the low-outside corner against RHH, epitomized by the 2015 change-up heat map. This pitch comes from the same arm slot as his fastball and, to the RHH, looks just like the fastball that Siegrist pounds inside. However, the fastball continues along this trajectory to the inside corner while the changeup fades away.

Siegrist’s execution of this strategy against RHH is critical to his success against them. When the fastball and change-up are on two different planes, like in 2014, Siegrist is less effective; that year, RHH compiled a .356 wOBA against him. When the pitches stay in the same plane like in 2015, Siegrist is at his best against RHH.

Importantly, Siegrist has no noticeable control issues against RHH. The core of each fastball heat map is within the zone, while the cores of the change-up heat maps lie near the edges of the plate. While the change-up core in 2016 is a bit worrying since it is up in the zone, it is still on the outer third of the plate and was set up by arguably Siegrist’s best fastball location.

Location vs. LHH

If location is the primary driver behind Siegrist’s success against RHH, it is also the biggest factor in his struggles against LHH as a member of the St. Louis Cardinals. Below are his fastball and curveball heat maps against LHH; since Siegrist rarely uses his change-up against lefties, I did not include it here.

St. Louis Cardinals
Source: Baseball Savant /
St. Louis Cardinals
Source: Baseball Savant /

These heat maps are much messier than those against RHH. Rather than working inside against LHH as he does against RHH, Siegrist opts to work the same side of the plate, now away from lefties. However, here Siegrist lacks a defined core, an indication that he has location struggles against LHH. Remember, Siegrist struggled to throw first pitch strikes against LHH as well.

In fact, Siegrist actually developed two cores in 2014 and 2016, one of which was entirely outside the strike zone. Siegrist’s erratic fastball location versus LHH results in more balls as he falls behind in the count. The cores he established inside the zone were generally high and outside, including his core in 2016 which leaked over the heart of the plate.

While Siegrist’s fastball location against LHH has proved inconsistent over his four seasons, his curveball location has actually been more refined. From 2013 to 2015, Siegrist threw a harder curveball which broke more like a slider. The location of this pitch was best in 2015, when Siegrist started the curve on the low-outside corner before letting it dive off the plate.

However, Siegrist’s curveball was never well-located from 2013 to 2015. In 2013 and 2014, Siegrist often missed high, which makes the pitch easier to recognize. From there, hitters can lay off balls out of the zone or attack the hangers. Additionally, in 2013 and 2016 especially, the pitch was often further off the plate than ideal or intended and, without above-average movement, would have been easy to lay off.

In 2016, there was a noticeable shift in Siegrist’s curveball location. Rather than focusing the pitch off the outside part of the plate, he kept the curve over the corner while driving it below the batter’s knee. The curveball’s core in 2016 was both the closest to the strike zone and the most focused. Unsurprisingly, Siegrist was better against LHH in 2016, limiting them to a .302 wOBA.