Analyzing Jered Weaver's Brilliant Start

Editor's note: I want to give credit to WiHaloFan for many of the ideas in this post. His recognition of the varying pitch speeds on each of Jered Weaver's strikeouts opened my eyes and enticed me to dig into the stats and do some research...

If you have paid even an iota of attention to the Angels and baseball in general this year, you don't need me to tell you how dominant Jered Weaver has been to start the season. After his first six starts, he leads the league in wins (6), strikeouts(49), ERA (0.99), innings pitched (45.2) and is tied for the lead in complete games (2) and shutouts (1).

Jered is, needless to say, at the top of his game and his pitching is simply sublime. He is in full control of his entire arsenal of pitches, locating and mixing speeds with expertise. His ability to throw any pitch in any count with confidence has kept batters guessing (and often whiffing) at nearly every pitch. Because of his dominance to date I was inspired to take a look at his pitch selection and results for every out he has recorded this year. We'll take a look at some of his stats after the jump.

First, let's take a look at his stat line for the season:

Pretty crisp and clean. Now some of the more advanced metrics:

One reason Jered's ERA is so low is because he's putting very few men on base, as is evidenced by his very low WHIP. His walks per 9 and hits per 9 are below his career norms by 3 and .5, respectively. As a result, we should expect these numbers to come up a bit, but not drastically. Similarly, his K/9 is up a bit from last year's 9.35, but he proved that that he is capable of pitching at that level for an entire season, so while there might be a drop in his strikeout rate, we can't assume his current numbers are fluky.

The two numbers that stand out in that line where we will probably see a lot of regression is in the batted balls in play and left on base percentage, both of which are uncharacteristically in his favor. BABIP for any given pitcher usually falls around .300, though some pitchers have career numbers higher and lower than that. In 2009 and 2010, Weaver's BABIP was .278 and .276, respectively, and over his career it is .280. Clearly, this year's number will rise over time, so expect Weaver to give up more hits down the road. The LOB% is also drastically in Weaver's favor. For league average pitchers, you can expect a LOB% of 70-72%, according to Fangraphs. Jered's career numbers have averaged out to 76%. So again, we can expect some regression here. Together, we can expect more batted balls to find holes in the defense, and those hits will lead to a few more runs, increasing Weaver's ERA and decreasing his strand rate. 

After looking at these numbers, it seems Weaver is getting pretty lucky with balls in play finding his defenders rather than the ground. But what about his contact rates? Is he getting more swings and misses than usual? Let's see:

When I look at those number, there isn't much that jumps out at me as abnormal. Batters are swinging at less of his pitches, both inside the zone and out. Batters are making contact with the ball at a lower clip than his career norms, but not by a significant amount. The Zone% is percentage of pitches seen inside the strike zone, so it seems batters are taking less pitches in the zone, but again not by a large margin. What is most striking to me is the increase in first pitch strikes, up 3.5% over his career average, and 2.5% over last year. Weaver is getting ahead of the batter at 0-1 more often this year which means he is dictating counts enabling him to use more of his arsenal to keep batters guessing. Last night's game against Oakland is a great example of this: Weaver threw a first pitch strike to the first 15 batters he faced. Being able to get ahead of batters early in the count puts the pitcher in the drivers seat during the at-bat, and Weaver has done a splendid job of this so far this year.

As for pitch selection, Weaver is doing an excellent job of mixing up pitch types and speeds. Last year, he utilized his four-seam fastball pretty frequently at 38.3% of the time, while throwing his slider, two-seam fastball, changeup and curve between 13-18% of the time. This year, Jered is showcasing his slider much more than last year while relying on his four-seam fastball less, though he isn't using his curveball and cutter as often. Take a look at the numbers from this year:

As WiHaloFan has pointed out previously, the range of his pitches is really impressive. Even with any given pitch the batter could see 5 and 10 mph difference on the same pitch, let alone the difference between his 94 mph fastballs and 71 mph curveball and 73 mph changeup. It's been talked about by analysts and hitters alike, not only is it tough to tell which pitch Weaver is throwing, but the range of speeds he can throw on each given pitch means the batter will be hard pressed to time his swing correctly. During my research I found this fascinating chart at Texas Leaguers showing the release point of all of his pitches:

via pitchfx.texasleaguers.com

I'm no pitching expert, but to me it looks like his release point is nearly identical every time he throws the ball. Along with his deceptive delivery, hitters have very few signals to tip which pitch he is throwing. Again, this is why we often see batters look lost at the plate and swinging at pitches like they have a blindfold on.

To conclude, I have compiled the pitch type for each of Weaver's strikeouts (for those of you interested in seeing the pitch type and speed for each strikeout by game click here, and the same info for all putouts by game and inning click here; KS is a strikeout swinging, KL is a strikeout looking, and KFT is a strikeout foul tip): 

Of all of his pitches, he has gotten a majority of his strikeouts on whiffs on his slider (12) with an additional 3 coming on looking strikeouts. His second most effective pitch has been his four-seam fastball with which he has accumulated 14 total strikeouts. As WiHaloFan noted in previous HaloLinks, the range of speeds is what is most impressive. If you look at a breakdown of his putout pitches, you'll notice clumps of similar pitches, and what I found is that he will use a lot of a certain type of pitch, say his four-seam fastball, his first time through the lineup, conditioning them to a certain pitch in a sense. When he faces the hitters the second time through, he'll often set them up with similar pitches they saw earlier then get them out with the opposite pitch, say a changeup or slider in this example. This goes back to the release point and deceptive delivery, which forces hitters to blindly guess at the pitch, often resulting in flailing bats way ahead or behind the pitch. I know this doesn't sound like a shocking and innovative strategy, but when the delivery looks the same on every pitch and the hitter sees a lot of one type of pitch, it makes it challenging to adjust. 

No one will argue that Weaver is pitching better than ever. It's hard to pinpoint the exact reason for his remarkable start, but it boils down to a few key points. His delivery and release point make it nearly impossible for the hitters to pick up the type of pitch coming at them, and even when they do Weaver has the ability to change speeds with each of his pitches and from pitch type to pitch type. Similarly, he has done a fantastic job of mixing up pitches to keep hitters guessing. He has also improved his first pitch strike percentage, which puts him ahead in the count and enables him to dictate at-bats and utilize his entire arsenal. His maturity, knowledge of hitters and control have all grown over the years and we are now seeing the fruits of his hard work. Of course, as with anything, there has been a bit of luck involved, so expect him to come down to earth a little. But overall, there is nothing to suggest that he can't continue his dominance over the course of the season and put himself into Cy Young contention. Who knows how long this magnificent display of pitching will last, but I suggest sitting back and enjoying the ride.

*Data via MLB.com, FanGraphs and Texas Leaguers