On Thursday, Blue Jays pitcher Marcus Stroman knocked an 0-2 Julio Teheran offering just over the right field wall at SunTrust Park for his first career home run. It was the third homer Teheran allowed in the game, bringing his season total up to 8 homers in just 9 starts and spiking his HR/9 up to a dismal 1.49 mark. Teheran’s ERA is now up to 5.47, and his FIP and xFIP suggest that his inflated numbers are fully deserved, partly due to his elevated home run rate. However, a closer look at Teheran’s numbers yields a starting revelation that might be a long-term problem for the Braves and their young ace: Teheran simply can’t pitch well at home.

First, here is a look at Teheran’s splits thus far this season (per BaseballReference):

Amazingly, Teheran’s OPS against at home is more than twice as high as his road OPS. While his walk rate and strikeout rate have been somewhat steady across his splits, and his BABIP suggests some regression to the mean in both conditions, Teheran has given up all 8 of his home runs at home this season. Interestingly, of those 8 home runs, 6 have been surrendered to lefty (opposite-handed) batters.

Over his career, Teheran has been relatively susceptible to left-handed batters, allowing an .800 OPS against lefties compared to just .582 against righties. The trend has continued this season, though it has been amplified a bit as lefties have amassed a .931 OPS compared to just .632 for righties. At home, the effect is even more exaggerated, as Teheran owns a whopping 16.68 ERA with an opposing OPS of 1.296 against lefties. Perhaps the most remarkable numbers that Teheran has put up come from his batted ball statistics against lefties at home, which are as follows (per FanGraphs):

There are three numbers to look at here that can perhaps shed some light on why Teheran has struggled so mightily at home. The first is his fly ball rate (44.4%), which is about 10% higher than league average but in line with Teheran’s career rate of 40.3% against lefties. But while he may not be allowing much more elevation to opposing lefties, the results of the fly balls he does give up have been disastrous: he owns a HR/FB rate of 30%, an enormous jump up from his career mark of 12.6% against lefthanders. HR/FB is most often used as an indicator of luck, and if Teheran’s struggles are just a product of bad luck, then perhaps this exercise is futile and Teheran will be just fine.

For the sake of this article, let’s assume that at least part of his elevated HR/FB rate is due to some real factor that isn’t just bad luck. In fact, the third chosen stat from Teheran’s batted ball numbers could be an influencing factor. Lefties are pulling an even 50% of hits against Teheran at SunTrust, a nearly 10% spike above his career numbers and more than 10% above the major league average. Away from SunTrust, that number balloons to 56.1%, suggesting that the trend is both consistent across all of Teheran’s starts and, given his success on the road, not necessarily the sole culprit for his struggles at home.

Looking at all of three of these numbers together constructs a fairly convincing story about Teheran’s season. He isn’t allowing more fly balls than before, he is allowing more balls to be pulled both on the road and at home, yet has seen a spike in his home run rate against lefties only at home. Could it be that SunTrust Park is becoming a haven for left-handed hitters?

Though it is still just mid-May and there is not nearly large enough of a sample size to definitively determine the effects of the new ballpark, there is some evidence that supports this theory. Of the 38 home runs hit at the Braves’ new ballpark (as of May 19), 22 have been hit by lefties. Additionally, of those 38 home runs, 21 were hit to the right side of center. These numbers don’t exactly jump off the page, but they moderately suggest that the right field power alley and the right field corner at SunTrust Park are especially cozy targets for left-handed sluggers. The right field corner sits just 325 feet from home plate and the right field power alley maxes out at 375 feet, which are short of the wall at Turner Field (330 and 390, respectively).

The early season returns at SunTrust Park would seem to tie a neat little bow on the story of Teheran’s season thus far. Lefties are pulling the ball more against Teheran, keeping the ball elevated and SunTrust Park seems to be doing the rest, allowing those fly balls to leave the yard at an alarming rate. There was a good deal of speculation that the Braves designed their new ballpark and the outfield dimensions with their superstar, Freddie Freeman, in mind. Indeed, Freeman seems to have taken an early liking to the ballpark, but Julio Teheran seems to have lost as much, if not more, as Freeman has gained. If the early season trends for Teheran and SunTrust Park hold true, the young Colombian and his club could be in for a long, homer-happy season.

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