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Julio Teheran struggled to beat lefties last year. Here's why.

Julio Teheran's struggles were obvious last season, but lefties gave the Braves starter more than he could handle.

Brett Davis-USA TODAY Sports

Repeating success from season to season isn’t the easiest task. Just ask [enter player who struggled one season after playing well]. Pardon my allusion to infinity, but the limit does not exist. If you’re looking for a case study in the opening phrase, look no further than Atlanta Braves starting pitcher Julio Teheran.

Coming into 2015 Teheran had enjoyed some success. The then 24 year old had posted an fWAR of 2.5 in 2013 and 3.2 in 2014, which looks good when combined with his sub-90 ERA- in both seasons. Oh yeah, his strikeout and walk rates weren’t too shabby either—striking out 20 percent of the batters he faced while walking ~6 percent. In short, Teheran’s success at his young age appeared to be nothing but a boon for the Braves’ future. Not only had they just secured him through at least 2019 (with a team option for 2020), but the Braves had an asset that would reach his prime years at the same time they expected to compete again. It appeared to be the ideal scenario for both sides, so naturally baseball had to intervene and muddy up the situation.

In case you weren’t already aware, Julio Teheran did not pitch as well in 2015. For most pitchers a 4.04 ERA isn’t terrible, and neither is a 4.19 xFIP. He was also able to strike out 171 batters in 200.2 innings, which translates to a 20.3 percent strikeout rate. That’s not all that bad for a young pitcher like Teheran. However, the Braves weren’t expecting him to be described as "not all that bad". They weren’t expecting him to be like most pitchers. Instead, Atlanta was hoping for him to continue down the path to ace-dom. To further himself from the crowd, not join it.

Back in June our very own Murphy Powell dug into what happened to the young right-hander, focusing on his batted ball profile and how it was changing due to where he had been locating his pitches. The conclusion? He was pitching lower in the zone, which led to an increase in ground balls and a decrease in fly balls. That was probably a good thing, as Powell noted an elevated HR/FB% would’ve plagued Teheran even further should he have given up more fly balls.

That theme stayed true all the way through the end of the season; however, it wasn’t the only reason for Teheran’s poor performance. There is no doubt it was a contributing factor, as Powell hit the nail on the head, yet he also had some hefty struggles against left-handed batters. Check out his splits taken from FanGraphs from last season:

vs L 91 422 0.297 0.387 0.507 15.2% 11.1% 17.8% 0.319 0.386 6.01 5.08
vs R 109.2 421 0.202 0.263 0.320 25.4% 6.2% 8.4% 0.255 0.257 3.07 3.44

The 422 left-handed batters Teheran faced put up a .297/.387/.507 slash line and .386 wOBA against him, which is astounding. To put that into perspective, there were just three pitchers who owned a higher wOBA against in 2015; Kyle Kendrick, Jeremy Guthrie, and Rubby de la Rosa. Not exactly the best company to be in. On the flip side, Alex Gordon had 422 plate appearances for the World Champion Kansas City Royals. His slash? .271/.377/.432 with a .351 wOBA. OK OK, I’m almost done. Here’s my last mean ‘LHB hit Teheran extremely well’ stat. Say you summed up all the lefties that faced Teheran last season into one hitter—we shall call them Player X—and compared said player to other hitters. Player X would rank 11th in wOBA out of the 211 MLB hitters last season with at least 400 plate appearances.

Just to further drive the point home, it’s safe to say he wasn’t too fond of left-handed hitters in 2015. As Powell described, even in June Teheran had begun to pitch down and away to LHB almost exclusively. Here is how it changed from over the last three seasons:

A move down in the zone is usually the goal of all pitchers, anyway. How many times have you heard the phrase, ‘I just couldn’t keep the ball down today’ postgame from a pitcher or an analyst reason that a pitcher got shellacked because he left the ball up in the zone? Moving down and out to left-handed hitters, in a vacuum, doesn’t alone lead to poor performance. Teheran did have success down there before, as evident by his 2013-14 RAA/100P heatmap:

2013-14 RAA/100P Teheran

Yet the reality of the matter is that, in Teheran’s specific case, moving down and away did lead to his poor performance against LHB in 2015. Against Teheran, lefties started to hit the ball better in that area, and it was made worse by giving them more pitches to hit in the same location.

2015 RAA/100P Teheran

He became predictable, and Major League hitters realized the pattern. That isn’t the only reason for his pitching woes last season, but it is the most notable. Teheran was basically in line with how he had thrown against righties thus far in his career, meaning that, in some respects, most of his overall struggles were derived from how southpaws hit him.

Breaking down his season further, he did try to make an adjustment. On August 2nd, a start in Philadelphia, Braves pitching coach Roger McDowell moved Teheran from the 3rd base side of the rubber to the 1st base side. You can clearly see it by looking at his changing horizontal release point on Brooks Baseball, but it is best that I show you through Baseball Savant screen grabs.

Pre-August 2nd:


Post-August 2nd:

Da August

The second position is where he would stay for the rest of the season, and over that period of time he did benefit from better numbers. On his glove side of the rubber Teheran would improve virtually across the board (statistically) compared to when he threw on his arm side. He did pitch better, and just two starts in liked the changes he saw.

Yet, what appears to have been a good move overall might in fact lead to further dichotomous splits in the future. Since the main point of this article is Teheran’s struggles against left-handed hitters, it would just make sense to look at how this move translated versus lefties. Did it help or hurt him? Well, a little of both. There was solid improvement on his four-seam fastball, but his changeup and two-seam fastball got hit hard.

When I first noticed this move, my first inclination was to look at how the latter two pitches performed. My thought process was that moving to the first base side of the rubber would not bode well for them for multiple reasons. First, the location of the pitches didn’t change. If anything, they were both still being located in the same place—down and away. Yes the changeup did come back a little more toward the strike zone than the two seam, but he still opted for the same general location as before. The important part is that it stayed away from the inner portion of the plate to left-handers.

Secondly, shifting to a position on the rubber that is on the opposite side of the location you most frequent would mean that the ball stays in the zone longer than it previously had. This would be the most prevalent in his two-seam and changeup, since Teheran throws those two pitches with a good amount of horizontal movement. This would translate to left-handed hitters finding even more success on the two aforementioned pitches because they would be able to track them for longer than before. Add in the fact that, due to his track record, there is no real worry of him going inside on a lefty, and that gives hitters the ability to sit on the outer portion of the plate from the start. Both of my initial thoughts turned out to be true, as lefties hit those two pitches well (taken from Brooks Baseball):

Pitch Count AB BAA SLG ISO BABIP Whiff/Swing
Sinker 163 34 0.324 0.471 0.147 0.333 11.76%
Change 106 35 0.400 0.629 0.229 0.394 20.97%

Of course, as with anything that has so many variables attached to it, my thoughts being validated could very well be a case where correlation does not equal causation. However, it just seems to me that moving away from the area you frequent the most with two pitches that move toward said area naturally doesn’t make much sense.

Summarizing Julio Teheran’s season, in general left-handed batters were his Achilles' heel. Walks were also an issue, but it is tough to overlook how and why southpaws produced against him as much as they did. Going forward it will also be interesting to see from which side of the rubber he chooses to pitch. Righties were never the issue, but the decision might come down to which side gives him an advantage against left-handed hitters. He is in good hands, though, as his pitching coach Roger McDowell is one of the better pitching coaches in the game. It sounds simple, but finding a way for Teheran to have success against lefties is key to him having a strong showing in 2016.

--All heatmaps taken from FanGraphs

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Shawn Brody is a contributor for Beyond the Box Score as well as a sophomore pitcher at Howard Payne University majoring in Business Management. If you would like to get a hold of him, please feel free to email him at or follow him on Twitter @ShawnBrody.