In 2006 at age 23, Jered Weaver took the majors by storm as he was called up to the Angels and made 19 starts with a record of 11-2 and a 2.56 ERA. The question then was whether or not his performance was sustainable. Despite his ERA, Weaver recorded a FIP of 3.90 and xFIP of 4.30 in that small sample. Most people that believe these are better indicators of true talent would agree that he would struggle to replicate his early success. Over his next two seasons, Weaver was able to make at least 28 starts with mixed results. Below are his ERA, FIP, and xFIP for each of those seasons, according to Fangraphs:
ERA FIP xFIP
2007 3.91 4.06 4.76
2008 4.33 3.90 4.28
2009 3.75 4.04 4.48
As a fly ball pitcher, Weaver has a career BABIP of .283 and HR/FB ratio of 7.9%. Both of these have allowed Weaver's results to outperform his peripherals. The BABIP is not too big of a surprise as extreme fly ball pitchers have generally allowed a lower average on balls in play. The HR/FB ratio has been consistently low and even more beneficial to a pitcher like Weaver who lets up a fly ball on nearly half of his balls in play. One cause of this has been Weaver's ability to generate a high number of infield fly balls. In his five years in the league Weaver's average infield fly ball rate was 13.1%. He is consistently among the league leaders in this category and it is a big reason he has been able to outperform his peripherals. Despite Weaver generating some successful results in the first four years of his career, he was still not considered one of the top pitchers in the league. In 2010, after putting up 4 very similar seasons, Weaver took a huge step forward.
Weaver improved upon his career numbers across the board in 2010. The most noticeable jump came in his strikeout rate. Below is Weaver's K/9 for each year of his career, also according to Fangraphs:
That 9.35 K/9 ratio was good for 6th in the majors. Even more impressive is that this jump in K/9 came in a season in which he decreased his BB/9 to a career low of 2.17 for a K/BB ratio of 4.31. Weaver was also able to induce ground balls on 36% of his balls in play and limit line drives to only 15.8%. The groundball rate is not too impressive on a league wide scale, but represents a career high for the extreme fly ball pitcher. The LD rate was good for 13th in the league last year. Put it all together and Weaver managed a FIP of 3.06 and xFIP of 3.51. Both marks are easily career bests. The question now is whether 2010 was a fluke for Weaver or just an example of a pitcher taking the next step as he enters his prime.
Looking further into the success of Weaver's individual pitches it becomes somewhat clear how he was able to have so much more success in 2010. Weaver was able to add 1 mph to his fastball. At the same time he was able to decrease the velocity on his curveball by 1 mph and his changeup by almost 2 mph. Not coincidentally, Fangraphs' Pitch Type Valuations has both Weaver's fastball and curveball as more successful in 2010 than in any year in his career. According to their valuations, Weaver's fastball was 13 runs above average and curveball was 9.7 runs above average. Over the previous three seasons, his fastball was generally below average and curveball was usually hovering just around league average. He has also began throwing his curveball a lot more to opposing hitters. Weaver threw his curveball 6.6% of the time in 2008, 8.6% in 2009, and 13% in 2010.
The increased success with these pitches has shown up in Weaver's results. In 2010, Weaver was able to induce hitters to swing at 33.5% of his pitches outside the strike zone. In 2009 he was only able to accomplish this on 25.2% of his pitches. When batters swung at pitches inside the zone they were able to make contact at a much lower rate than previously in Weaver's career. Overall he was able to increase his swinging strike % to 11.2% which represents a large jump from his career average which was jsut above 9% before 2010.
In 2010, Jered Weaver was able to add velocity to his fastball and decrease the velocity on his off speed pitches. At the same time he was able to add a bit more vertical movement to his curveball. He went from a pitcher with a couple slightly above average pitches to a pitcher with four above average pitches. As a result he showed that he can get hitters to chase pitches out of the zone and can force swinging strikes at a greater clip than ever before in his career. He showed the ability to legitmately improve all his pitches and use those pitches in an effective way. I don't expect believe this success is a fluke, but instead a step forward for Weaver. I look for him to continue to improve these pitches and solidify his place as one of the best pitchers in the American League.