By Ben Gellman
Crawdads hurler Matt Thompson has added a new piece to his pitching repertoire this season: a cut fastball. It’s a pitch that more and more pitchers in both the professional and amateur ranks are turning to, and its popularity is due in no small part to its success at the major league level.
The term “cut fastball” originally applied to a ball that had been illegally scuffed, scratched or cut so as to disrupt its airflow in flight and produce an overlarge break. Since then, it’s evolved to apply to this pitch, a hybrid of sorts between a standard fastball and a slider. It breaks in on left-handed hitters when a righty throws it, and the key is that it breaks late. Since the time it takes for a pitch to reach the plate is less than two seconds, batters must make incredibly fast judgments on what a pitch is before they swing. Because the cutter breaks so close to the plate, it’s often too late for a hitter to adjust.
The cutter came into vogue after the sensational results Yankees closer Mariano Rivera got with it. Rivera has relied on the cutter for nearly all of his superlative career, and the numbers don’t lie. Rivera’s wonder-pitch has gotten him the top ERA among active pitchers, the best WHIP (walks plus hits divided by innings pitched) of any pitcher since 1917, and the second-most saves of any pitcher…ever.
This video demonstrates what makes Rivera’s cutter so effective. As you can see, it’s so close in looks to his fastball that hitters are just bamboozled.
While I wouldn’t compare Thompson’s cutter to the Sandman’s just yet, he’s gotten excellent results from it this season. Thompson has a 3.26 ERA in nine starts, and has struck out 53 batters in 47 innings. What’s more, SAL hitters are mustering just a .228 batting average against him in 2011, down precipitously from last year’s .304 mark. He’s also allowed just 0.57 homers per nine innings, the stingiest rate of his career. He’s inducing ground balls at a higher rate, and he carries an ERA of 1.57 over his last six starts.
Is the cutter alone the explanation for all of this improvement? Probably not. But Thompson’s new weapon has certainly proven formidable against SAL foes.