Survival of the Fittest: Evolution of an Ace

Over the past three years Weaver has been the unquestioned number 1 in the Angels’ rotation. 2011 was Weaver’s best year by ERA+. ERA+ is a stat that our front office really likes. It takes a pitcher’s ERA, adjusts it for park factors, and compares it to the league average. He had a 156 ERA+ in 2011 and anything over a 100 (league average) is good.

2010 was Weaver’s best year by FIP. FIP, or Fielding Independent Pitching, is a stat that measures what it is believed the pitcher can control and converts it to an expected ERA, assuming they had league average defense backing them up. FIP assumes that a pitcher has no control of how his fielders play the ball behind him and therefore no control of what happens to balls hitters put into play. The things a pitcher can control are called “The Three True Outcomes” and they are: walks, strikeouts, and home runs.

The difference between Weaver from 2010-2012 and when he first entered the league is easy to see. He cut down his walk percentage from around 7.3% to 6.1%. He cut down his home runs per 9 innings from 1.05 to around .9. He also increased his use of his curveball (2010) and introduced his no-seam fastball (2010) and his cut fastball (2011) to keep hitters more off-balance. All of these changes coincide with a dramatic reduction in his Batting Average on Balls in Play (BABIP) to below or well below league average. Basically this means fewer balls hit by batters in the field of play end up as hits.

The bad news that causes people to question Weaver is twofold: Weaver’s Fastball velocity has dropped from 90.1 to 88 or 87 and his strikeout percentage has dropped from 25.8% (2010) to 19.2% (2012.) With these lower speeds and lower strikeout rates can Weaver continue his success or will he wilt? Will it happen in 2013, when we need him to stabilize our perceived weak rotation? Can he sustain his previous success as he ages?

The more I dug into his numbers the more I learned about how he pitches and how he is continuing to evolve as a pitcher. Weaver has succeeded in three different ways in his career and I want to first talk about how he’s done it to see if he can continue.

When Weaver’s first came up to the big leagues in 2006/2007 he was relying primarily on his 4-seam fastball and his deception to strikeout hitters. His cross firing delivery made hitters uncomfortable and made his fastball seem faster than it was. This allowed for more infield fly-balls (automatic outs) and more strikeouts (21.4% in 2006 and 20.4% in 2008.) He struggled with runners getting on base due to his higher walk rate during this time, which would often come back and bite him. His BABIP was fairly normal in the league. How well he performed was related to his defense and how lucky he was when he allowed the Homerun, which he was prone to as an extreme fly-ball pitcher.

As an important note, being a fly-ball pitcher is not always a bad thing, as many people tend to believe today. Often we hear ground-ball pitchers being praised as the best and this is due to the rise in the value of “the Three True Outcomes” in baseball. The reasons analysts value ground-ball pitchers more now is because it is hard for a pitcher who gets more ground-balls to give up many homeruns (the worst of the three outcomes.) A fly-ball pitcher is obviously more apt to give up HRs because he has more chances to do so. What is often not realized is that when we compare ground-balls to fly-balls we find “fly-balls that aren’t home runs have a mere .167 batting average compared to ground-balls that have a .236 batting average.” If a pitcher can consistently keep the balls in the yard or runners off base than he can do well giving up fly-balls.

Now, sometime in 2009 Weaver came to believe that allowing batters to put the ball in play was not a terrible thing. Around that time he was convinced he needed to get deeper in the game and not worry as much about striking hitters out. He began his journey of getting early count outs, limiting base runners, and pitching deeper into games, but can we measure this?

First, Weaver began to change his pitching repertoire. He began using his no-seam fastball and increased his curveball use from 8.6% in 2009 to 13% in 2010. His curveball use has since leveled off at around 10.6%. His curveball creates a different look for him and it is a good pitch for him to confuse the hitters timing since it clocks in around 70 MPH, or 17-20 MPH slower than his fastball. His no-seam sinker also helps to reduce line-drives and gives him another look to the hitters. These also could serve to create more weak contact by hitters and easier outs.

Second, his walk percentage dropped in the 2010 season from 7.5% to 6% and remained at 6.1% in 2012. He wanted to pitch to more contact in 2009 but as he continued to walk hitters he found it detrimental to the tune of a 3.75 ERA that year. He seems to have worked to reduce his walks the following year. The only thing this seems to coincide with is his introduction of the sinker and increased use of his curveball, as mentioned earlier. Not sure if that helped him with control but the fact remains he did limit his free passes which really helped to turn it around for him.

Finally, Weaver pitched more innings. In 2008 he pitched only 176.2 innings. He increased that in 2009 to 211 but his success didn’t really start until he reduced his walk rate in both 2010 and 2011 where he pitched 220+ innings a year. He got deeper in games and became more of a workhorse by keeping the bases clearer.

This leads us to Weaver’s second style of pitching which was to remain a fly-ball pitcher but reduce both solid contact and runners on base. With fewer runners on base when someone hit a homerun, he could limit the damages. Also, they wouldn’t be able to square up his curveball or sinker and hit as many line-drives off him. 

We can see this in his reduced line-drive percentage in 2010. This is important for a pitcher because hitters have a batting average around .600 on line-drives. We know there are two things that help to prevent line-drives: “1) good sinking pitches and; 2) throwing hard.” Weaver’s good velocity in 2010 and his introduction of his no-seam sinker and curveball resulted in an immediate LD% drop of 3%, but it wasn’t a sustainable drop. The reason it wasn’t sustainable could’ve been due to Weaver’s drop in velocity in 2011 because “faster pitches in general seem to lead to a lower LD%” and slower pitches do not. 

This leads us to how Weaver adjusted to these changes last year. He seems to have begun to reinvent himself a third time via the influence of pitchers on his team. 

Near the end of Scott Shields’ career, in 2009/2010, he began to teach Weaver his no-seam sinking fastball. As we already mentioned, Weaver worked hard to learn it and brought it into games in 2010. This helped Weaver to reduce his reliance on his 4-seam fastball. In 2009 Weaver threw the 4-seamer 47.4% of the time. In 2010 he threw the 4-seamer 38.2% and the no-seamer 17.4%. Last year Weaver increased his no-seam fastball even more to a 24.6% clip and decreased his 4-seam use to only 28.3%.

Sometime between August 2010 and the start of the 2011 season Weaver began to learn Dan Haren’s cut fastball. As Weaver’s fastball velocity was dropping in 2011 he began to add the cutter into his repertory of pitches 6% of the time. Weaver used his 4-seam FB even less in 2011, only 30.5% of the time, to allow for his increased use of his other two fastballs. 

With Weaver losing more velocity on his fastball last year he decided to transition away from being an extreme fly-ball pitcher. With his increased cutter use (9.0%) and the increased use of his sinker (24.6%) he has reduced his overall fly-ball percentage to 42.8% from his career average of around 48%. This is still well above the league average last year of 33.9% but it is a significant move down for Weaver. Also his GB/FB rate went up considerably from an averaging around .7 to .84 in 2012. This means more ground-balls as compared to fly-balls. This again is still well below the league average of 1.33 but a significant change for Weaver. 

With all this movement on his fastball he is no longer relying on the 4-seam fastball and the strikeout to get hitters out and his K% has dropped accordingly back to 19.2%. While still respectable it is only slightly above the league average of 18.7%. But while reducing strikeouts he has also dramatically increased his double play percentage from his career norm of around 5% to last year’s 11% rate (league average.)

With all these changes Weaver’s BABIP has remained well below the league average and this has really been his advantage. This started in 2009 and 2010 when Weaver still had his hard fastball with deception. As his velocity decreases Weaver is trying to maintain that lower BABIP with ball movement. In an article on FanGraphs about pitcher’s BABIP this quote appeared after a description about pitch types and their effect on BABIP, “It seems movement is a lot more important than speed when it comes to fastballs and BABIP.”

Weaver is challenging the accepted norms of the sabermetric world. Back when the idea of “The Three True Outcomes” was postulated there was still more to be learned. These lessons come from the outliers. Weaver is one of those outliers. He continues to succeed where he should not be able to. He has, what many would consider, an unsustainably low BABIP with a declining strikeout rate. This should be the obvious sign that he will regress to the mean, but he has not done so. 

Weaver is showing us all that there is a lot more that pitchers can control than just walks, strikeouts, and home runs. Recently a lot of work is being done to validate a fourth true outcome, infield fly-balls. Other work, like the article linked to here that I’ve quoted from, have shown that there are correlations between the outcome and how a pitcher chooses to pitch. 

Weaver has chosen to give up the holy grail of strikeouts and simply work on what he can. He has reduced walks and increased weak contact through movement and changing speeds. He utilizes the tools he has, develops more as needed, and does all he can to limit his opponents BABIP (although he probably sees it as limiting their batting average.) 

With Weaver’s ability to evolve and learn I believe that he can continue his success as the ace of the Angels’ staff. Could things go wrong? Sure. But will they? Not likely. This is because Weaver will adjust to them. That is what great players do. The league adjusts to them and they adjust to the league. Weaver will make it work, no matter what the velocity.