Who is the Real Julio Teheran?
Let’s try to answer some of the questions surrounding Braves ‘Ace’ Julio Teheran.
As I was gathering information for this article, I noticed that the writers at Beyond the Box Score have done some interesting analysis about Teheran in the last two years, complete with great graphics that I’m not including here for sake of space. I’ll summarize their conclusions and link to their work, and add a bit of insight from my own observations before finishing up.
- Murphy Powell demonstrated that Teheran threw pitches up in the zone far less frequently during the first half of 2015, and that this may have led to his reduction in fly ball rates and strike out rates, and an increase in BABIP via higher line drive rates.
- Kevin Ruprecht found that despite an overall trend of pitching down in the zone more often, Julio kept using his four seam fastball up in the zone as he had in the past. He used this pitch more often in the second half than in the first, which Ruprecht reasons may have led to much improved HR rates and K rates later in the season.
- Lastly, Shawn Brody dissected Teheran’s struggles against lefties in 2015, including some interesting analysis of Julio’s move to the opposite side of the rubber in August of that season.
Those three pieces together serve as an excellent analysis of Julio’s down year in 2015. I feel that there is one more factor that needs our attention, though.
Swing Rates on Pitches Outside of the Strike Zone
I’ve already mentioned that Julio walked more batters, struck out fewer of them, and surrendered a noticeably higher rate of HR per fly ball in 2015 relative to his work during 2013 and 2014. The fellas from BTBS above hit on some interesting factors that may have led to this. But check this out.
The gif below shows swing rates against Teheran’s pitches by zone. There are two ‘slides.’ One shows the rates during his good work during 2013 and 2014, and the other during his poorer work in 2015 (dates are at the top). The ‘hotter/redder’ the zone, the higher the swing rate in that zone, and the ‘colder/bluer’ the zone, the lower the rate. This view is from the catchers perspective, and the 3X3 zone in the middle represents the strike zone.
Look at the drastic difference in swing rates outside of the zone in the two heat maps. It’s very plain to see: batters offered at pitches that they had a low chance of success against (i.e. balls) far more in Teheran’s first two seasons as a full time starter in Atlanta. In 2015, that trend came to an abrupt halt.
It’s clear that it’s to hitters’ advantage to lay off balls outside the zone. Pitchers will have a tougher time striking you out if you don’t chase, and you will earn more walks this way, as well. Further, if you make contact on pitches outside the zone less, you will naturally reduce the tendency to ‘get yourself out’ via weak contact.
Julio Teheran built his early career success on better than average strike out and walk rates, and by limiting average fly ball distance with great success. He went from above league average in those areas to below league average in 2015, a season during which hitters also made contact with pitches outside the zone far less often. That does seem pretty compelling.
Why would this happen?
Scouting Reports: it’s very possible that teams wised up. If fans and bloggers can access a pitcher’s habits, just imagine what the data analysts employed by MLB teams have at their disposal. Perhaps the book is out on Teheran’s tendency to pitch out of the zone to get punch outs and weak contact, and the league has adjusted. So far in 2016, it appears batters are chasing a bit more than in 2015, but still less than the previous two seasons.
Command: not all balls outside of the zone are created equal; batters will chase a fastball 3 inches north of a strike much more often than a pitch all the way up in their eyes. The same of course applies anywhere in the zone. An overall decline in ability to throw pitches in an area where batters are likely to chase could have fueled the decreased swing rates outside the strike zone.
Pitch Sequencing: batters are more likely to swing at ‘pitcher’s pitches’ when they have been successfully ‘set up’ by the pitch sequencing decided upon by the catcher and the pitcher. During 2015, Teheran threw to a new group of catchers in A.J. Pierzynski, Ryan Lavarnway and Christian Bethancourt. Perhaps these three did a worse job calling the game than Julio’s previous battery mates.
It’s difficult to pin point what may have led to the reduced swing rates outside the zone in 2015, but it’s pretty clear that the trend contributed to undesirable outcomes for Teheran.
Looking into the Crystal Ball
More from Tomahawk Take
- Braves News: New Year’s Eve comes with several questions about the 2023 Braves
- Braves News: How the Braves got their name, mailbag, more
- Atlanta Braves Mailbag: New Year’s Edition
- Braves News: Atlanta makes a pair of trades, prospect debuts, more
- Atlanta Braves History: How the Red Stockings became the Braves
2015 was a troubling result for Julio and the Braves. However, we can find some optimism in that he finished the year with positive results during the last two months, and that his numbers are trending in the right direction in 2016 so far. Indeed, his current strike out rate matches his best career mark from 2013, his average length on fly balls is back to a respectable level after sky rocketing to over 300ft in 2015, and his HR/FB rate is back down to league average. The walks continue to happen more often than during 2013 and 2014, but they are improved from last season.
That last sentence encapsulates where I think Julio Teheran is right now. He’s better than last year, but not flashing 2014 results, either.
Given his career so far, his start in 2016 should make us feel pretty confident that he is better than the pitcher we saw last season. And it’s not even like he was that bad last year. That being said, there are other trends that should make us skeptical that Julio will consistently dominate the league like we witnessed in his first two seasons as a part of the Atlanta rotation.
Time will tell, as Teheran and the league adjust back and forth to one another in the cat-and-mouse typical of the sport at its highest level. He has good stuff, but as 2015 showed us, he’ll need more than that if he is to regain his early career form and stay at the top of what may be a very good Braves rotation in the future.