As Sports Illustrated's Albert Chen noted earlier this month, the rise in popularity of the cut fastball is one of baseball's biggest storylines this year. The pitch, thrown a few miles per hour slower than a conventional fastball, is an effective weapon against hitters on both sides of the plate. For instance, left-handed pitchers have a .307 Weighted On-Base Average against both lefty and righty hitters with the cutter, throwing strikes to lefties about 65 percent of the time and over 67 percent to righties. Overall, cutter usage among major league pitchers has steadily increased from 1.8 percent of all pitches thrown in 2008 to 5.2 percent in 2011.
Two lefties highlighting the cutter trend will take the mound in Philadelphia this afternoon, as Jon Lester faces Cole Hamels. Lester's cutter, thrown more than a quarter of the time, is holding hitters to a .214 wOBA that ranks fifth among starting pitchers. Hamels is throwing his cutter about 15 percent of the time and places a spot ahead of Lester with a .196 wOBA against. Lester and Hamels are both getting great results with the cutter, though they're using the pitch in different ways.
For Lester, the cutter is a chase pitch that he uses to rack up strikeouts. Look at the pitch frequency of Lester's cutter:
He's trying to get lefties to chase the pitch off the outside corner, while burying the cutter in on the hands of right-handed hitters. Lester has thrown about 38 percent of his cutters within the strike zone, compared to the 51 percent big league average. And hitters are obliging by chasing 41 percent of Lester's cutters thrown out of the zone, way above the 30 percent average. Lester's cutter is his go-to pitch in two-strike counts, and he has used the cutter to record 51 of his 100 strikeouts this season.
Hamels, on the other hand, places his cutter in the strike zone more often:
Fifty-one percent of Hamels' cutters have been thrown in the zone. Hamels isn't getting as many swings and misses as Lester -- his miss rate with the cutter is 19 percent, compared to Lester's 28 percent and the 20 percent average -- but he is getting more grounders than his Red Sox counterpart. Hamels has a 67 percent ground ball rate with the cutter, while Lester is getting grounders 53 percent and the average is 43 percent. In two-strike counts, Hamels still prefers his fastball and changeup, and he has used the cutter to get just 13 of his 108 punch outs.
Lester and Hamels use the cutter for different purposes, but the end result for the batter is usually the same: a return to the dugout.