The A's are off to a decent start to the 2011 season, going 9-8 in their first 17 games. They currently lead baseball in ERA and are fourth in pitching WAR because of the strong performances of the starting rotation, led by Brett Anderson and Trevor Cahill.
Anderson has gotten off to a great start this season, pitching to a 1.63 ERA (2.57 xFIP) with a 6.83 K/9 and a 0.98 BB/9 rate. He has only allowed 26 hits (zero home runs) in his 27.1 innings pitched this season.
Anderson is not throwing as hard as he did in 2009-2010, averaging 90.6 mph in 2010 compared to 92.6 mark in 2009 and 92.1 last season. However, he has made the adjustment and has thrown more breaking balls early in his 2011 campaign (PITCH/FX has labeled them all sliders, but he does throw a curveball).
This season Anderson has thrown fastballs 44 percent of the time (both four- and two-seamers), breaking balls at 49 percent (sliders and curves) and changeups at seven percent. The ratio last season was at 50.9 percent fastballs, 40.9 percent breaking balls and 9.3 percent changeups.
The increase in sliders and curveballs have benefited Anderson. Already a dominant groundball pitcher, he has increased his percentage from 54.6 last season to 65 percent in 2011. In addition, Anderson's swinging strike percentage currently sits at 8.8 percent, up from 6.7 last season.
Anderson threw his best game of the season last night against the Red Sox while showing dominant breaking balls. He recorded eight strikeouts, four hits, one walk, a four GB/FB ratio and zero runs in eight innings pitched. Anderson recorded all eight of his strikeouts on breaking balls (seven on slider and one on curve), and recorded a 23 percent swing and miss rate on both pitches combined. Anderson used his fastball 47 percent of the time, while recording a 7.8 percent swing and miss rate on the pitch.
Trevor Cahill, like Anderson, has made some early-season adjustments after having a very good 2010 season. Cahill's sinking fastball has lost some velocity early on this season, down to 89.6 mph from 90.4 mph last season.
Even with this slight decrease, Cahill has increased his K/9 rate from 5.40 last season to 9.59 this season. Cahill is recording more swinging strikes. His swinging strike percentage currently sits at 9.1 up from his 5.9 percentage last season.
Cahill fastball percentage has decreased this season (64.1 percent in 2010 down to 58.4 in 2011), while slightly increasing the use of his changeup (18.3 to 20.8) and increasing his curveball usage (13.1 to 20.8). In his most recent start against the Tigers, Cahill recorded a 26.67 swinging strike rate on his curveball, a 16.67 on his changeup and a 5.79 rate on his fastball.
Most importantly, the increased usage of his off-speed pitchers has not affected Cahill's ground-ball rates significantly. He is currently inducing ground balls ate a 53.6 percent rate, only slightly off from his 56 percent rate last season.
It remains to be seen whether Anderson and Cahill stick to their approached for the entire season, but it is clear that the A's can make a run at the AL West because of their talent and the depth of the rotation.