To say nobody expected much out of Aaron Harang is a fairly massive understatement. He was released by the Cleveland Indians, who aren't exactly flush with pitching and picked up by the Braves, seemingly out of desperation due to a spate of injuries to their starting staff. At best he was looked at as a stopgap solution that would maybe allow the team to tread water until Mike Minor, Ervin Santana and Gavin Floyd returned. At worst he was seen as a money move that was slightly cheaper than Freddy Garcia, to the point of some writers openly lamenting the loss of "Big Chief" and questioning the wisdom of signing Harang in his stead.
Harang, for the moment has completely shut down all concerns.
First, let's look at Harang's traditional statistic results, so we can get a grasp on just how incredible his performance has been:
In 3 starts (18.2 IP) he's 2-1, with a 0.96 ERA, 9 H, 2 ER, 2 BB, 17 K, .145 Avg against. Which, yeah, regardless of what you think of the worth of any of those stats, especially in a small sample, as predictive measures, that's incredible production. Even looking at some of the more advanced statistics, fangraphs' WAR and FIP, Harang is still pretty incredible at 0.6 and 2.28 respectively. However, when we look at Harang's xFIP, (4.00) a more complicated picture emerges.
First, let's discuss exactly what FIP is for a second, without going into the minutiae. Essentially FIP is a stat that attempts to take the quality of the defensive play behind a pitcher out of the measure of the pitcher himself. It does so by essentially only considering a pitcher's strikeout, walk and home run rates, since the defense controls everything else that happens other than those three outcomes. Harang has had excellent defense played behind him, as evidenced by the fact that his actual ERA is over a full run below his FIP. However, it's a bit more complicated than that, as there is some issue of weak contact, given that Harang is getting hitters to chase and make contact on a lot of pitches out of the zone.
Harang's zone percent, a measure of simply how often a pitcher throws a ball in the strike zone (as measured by pitchFx, not umpire calls), is 46.8%, compared to a league average of roughly 50%. This puts Harang right around the bottom 1/3 of pitchers in percentage of pitches thrown that are in the strike zone. While typically this is a bad sign, showing a pitcher has a lack of command, it isn't if the pitcher can convince the batters to chase, which Harang has. Harang has managed to get hitters to chase out of the zone 30.5% of the time, which is good for top 1/3 of the league. So, essentially Harang is throwing out of the strike zone more than the majority of pitchers, and getting hitters to swing at those pitches outside the zone much more often as well. How does that manifest itself in the results?
When batters are swinging at pitches out of the zone by Harang, he's feasting in just about every way, save one (which we'll get to shortly). First, he's getting them to swing and miss a lot, as he's getting hitters to swing and miss 52% of the time, which is significantly above the league average for pitches outside of the zone. Even when hitters do make contact on his pitches outside the zone, they're only putting the ball in play 16% of the time, indicating that when they aren't making contact they're mostly just fouling pitches off, this puts Harang in the top 5% of the league. Fouling pitches off a lot is a good indicator in two ways, first it gives the pitcher a free strike, but it's also an indicator of weak contact. Which brings us to the next aspect of how Harang has performed on pitches out of the zone, he's only allowing a .056/.292/.056 triple slash on pitches out of the zone, with a .125 BABIP (batting average on balls in play).
At first, that BABIP may seem anomalously low (considering that the average all around BABIP for an average pitcher is in the neighborhood of .300), but consider that this is on balls out of the zone and Harang's other peripherals indicate he's getting a lot of weak contact on such pitches (remember the only 16% balls in play). That .125 BABIP on balls might just be legitimate.
The one ugly side of Harang's pitches out of the zone has nothing to do with him however. He isn't getting very many called for strikes. The league average is about 10% of pitches outside of the strike zone get called strikes, whereas Harang is only getting about 7.5%, this is a significant difference, and has been mostly pitching staff wide. This seems to mostly be a result of moving from one of the game's best pitch framers, in Brian McCann, to one of the league's worst, Evan Gattis. If Harang was getting more called strikes out there, he would be even more deadly.
Since we've mostly talked about the good, and real aspects of how Harang has achieved his excellent results, let's now look at the other side of the coin, as Harang does have a few aspects indicating he's been a bit lucky as well.
First, Aaron Harang is yet to give up a home run. Harang is a fly ball pitcher who, throughout his career, has typically had a 10% HR/FB rate. Right now, obviously, he's sitting at 0%. That's going to change, and it's completely the explanation for why his xFIP sits at 4.00, while his ERA, and to a lesser extent, his FIP are so microscopic. xFIP essentially does what FIP does, but also gives the pitcher a league average HR/FB%. The idea being that in small samples (like three games pitched) HR/FB rate is highly random and takes a lot of innings to stabilize. A pitcher getting lucky with home runs goes a long way to explaining his success or lack thereof in small samples.
Secondly, Harang has stranded 86.7% of the runners he's put on, which is well above his career norm of 73%. Now, part of this could be simply that he's pitching better, as better pitchers tend to strand more runners, but some of it is also simply good luck most likely.
Finally, Harang is only allowing a .191 BABIP. Now some of this may be due to weak contact, but certainly not all of it. To expect a pitcher to maintain a .191 BABIP over the course of the season is pure folly.
In summation, just as you'd expect from a guy who has put up mind boggling numbers from out of nowhere, Harang's start is a mix of some real skill and a lot of luck. Harang does seem to be getting hitters to chase, whiff and make weak contact with good stuff. However, he's likely to run into some stretches of giving up homers, walking guys and having a lot of seeing eye hits.
Harang has seen respectable fastball velocity (90.2 MPH) and excellent movement (averaging 3.3 fps of horizontal movement with 13.2 fps of vertical movement, which are the top 15th and 27th percentiles respectively). Thus, I believe Harang is probably better than we initially believed, at least if he maintains the velocity and movement we've seen thus far. However, he's obviously not going to maintain anywhere near a sub 1.00 ERA, or even anywhere in the 2's. The interesting question is if he can keep it in the mid 3's to low 4's, an outcome for which I believe the Braves would be more than pleased with, especially given what we've gotten out of him when we needed him most, in the absence of Minor, Santana and Floyd.