Weaver's Devastating Fastball

Jered Weaver of the Los Angeles Angels of Anaheim and starting pitcher for the American League All-Stars owns the most devastating fastball in the majors this season.  In plate appearances ending on a Weaver fastball, he recorded the lowest weight on-base average (wOBA) of any pitcher (min 200 PA on fastballs):

Pitcher	Team	Fastball PA	wOBA
Jered Weaver	LAA	242	0.225
Erik Bedard	SEA	201	0.243
Jair Jurrjens	ATL	223	0.255
Cliff Lee	PHI	270	0.259
Jordan Zimmermann	WSH	246	0.262
David Price	TB	350	0.270
Ryan Vogelsong	SF	228	0.270
Matt Cain	SF	271	0.272
Justin Verlander	DET	292	0.274
Bartolo Colon	NYY	296	0.274

Weaver manages to keep his fastball away from both lefties and righties.  The following graph shows his pitch loationa and movement against left-handed batters:

Jered Weaver, fastball vs. LHB, 2011. Location on the left, movement on the right.Note the great movement toward the left-handed batter.  Weaver can start this pitch outside, and the break brings it back over the outside corner.  Even when he misses, batters sometimes go after the pitch, resulting in a swing and miss.  His wOBA against lefties on his fastball is .224.

Against right-handed batters, he works the other side of the plate.

Jered Weaver, fastball vs. RHB, 2011. Location on the left, movement on the right.Note that Weaver gets even more lateral movement with his fastball against right-handed batters.  He starts the ball inside, and then it breaks over the outside part of the plate.  Batters see a pitch they can pull, but it ends up a pitch they should be driving the other way.  Instead of getting good wood on the ball batters get weak ground balls or flies bunched in the middle of the outfield.  That helps him to a .226 wOBA against righties.

Chatwood Finds Footing in Majors

Tyler Chatwood faced a daunting task when the Angels inserted him into the starting rotation this past April. The 21-year-old entered the year ranked as a top-100 prospect according to Baseball America, but he had all of 6.2 innings of Triple-A pitching under his belt and spent most of the 2010 season between High-A and Double-A. Chatwood's lack of upper-level experience showed in the Spring. But he has improved each month:

April: 0.67 K/BB ratio, 6.23 Fielding Independent Piching (FIP)

May: 1 K/BB, 4.01 FIP

June: 1.62 K/BB, 3.34 FIP

Chatwood's percentage of pitches thrown within the strike zone has increased from 44.7 in April to 47.9 percent in May and 48 percent in June. Consequently, his strike percentage has climbed: 55.4 percent in April, 59.2 percent in May and 60.6 percent in June.

The undersized right-hander relies heavily on a fastball that sits around 93 MPH and tops out at 97, throwing the pitch over three-quarters of the time while mixing in a few upper 70s curveballs and low-80s changeups. Chatwood is doing a better job of hitting his spots with his fastball, getting the pitch to cross the plate at the hitters' knees instead of missing to his armside:

Frequency of Chatwood's fastball location in April

Frequency of Chatwood's fastball location in May

Frequency of Chatwood's fastball location in JuneChatwood placed his fastball in the zone just 47.1 percent of the time during the season's opening month, but that figure bumped up to 47.8 percent in May and sits at 52 percent in June. For comparison, the league average is slightly under 52 percent.

His better-located fastball has been much more successful. Chatwood's heat had a .411 Weighted On-Base Average against in April. In May, that fell to .361. This month, Chatwood's fastball has a .290 wOBA against that bests the .338 league average.

With nascent breaking and off-speed stuff, Chatwood is certainly a work in progress. But at least his fastball has turned into a legitimate weapon with which he can combat big league hitters.

Erick Aybar and the Inside Strike

Erick Aybar (LAA) hit well in 2009, posting a .312/.353/.423 slash line, good for a wOBA of .334.  In 2010, that dropped to .253/.306/.330, a poor .282 wOBA.  So far in 2011, Aybar's averages are back up.  What changed from 2009 to 2010, and has it changed back?

Aybar is a switch hitter, with most of his at bats coming against right-handed pitching.  In 2009, umpires gave Erick the benefit of the doubt on pitches on the inside corner of the plate.

Erick Aybar, called strikes from right-handed pitchers, 2009.Umps called strikes wide on Erick, but he could take the inside pitch, and force pitchers to move farther over the plate, a better hitting zone.  In 2010, umpires were not as generous.

Erick Aybar, called strikes from right-handed pitchers, 2010.While he still got the low strike called a ball, the inside edge of the plate reverted rightfully to the pitcher.  You can see how this might hurt a batter.  He was hitting in pitchers counts more often, and right-handed opponents didn't need to move over the center of the plate as much.  His strikeout rate against RHP went from 10.6% in 2009 to 14.6% last season.

What about in 2011?

Erick Aybar, called strikes from right-handed pitchers, 2011.Erick gets a big chunk of the lower, inside part of the plate.  The upper inside edge still belongs to the pitcher.  With almost one quarter of the zone going Aybar's way, it no wonder his slash line is back up to .342/.364/.425 and his strikeout percentage is now to 11.3%.  I would be dubious of that much of the zone going his way the full season, but if can at least keep the lower inside edge, he might post good numbers again.