SAN FRANCISCO -- Towel-snapping is widely considered a form of juvenile locker-room entertainment. For Giants left-hander Jeremy Affeldt, it's a useful practice tool.
Affeldt is among the handful of pitchers who try to refine their delivery by simulating it while gripping a towel in their throwing hand. Ideally, the free end of the towel should flick through the air like a serpent's tongue, not swish loosely in a semi-circle.
"When that towel snaps out, your mechanics are right," Affeldt said.
Recently, Affeldt has maintained his form nicely. He had made five consecutive scoreless appearances entering Tuesday, striking out four and walking none in four innings. Opponents were only 1-for-11 (.091) with runners in scoring position against Affeldt, who signed a two-year, $8 million deal last November.
Affeldt attributed much of his effectiveness to his towel time, which he repeats almost daily in the bullpen before batting practice. All it takes, he said, is between 10 and 20 "throws" to hone his rhythm and timing.
"I always have to stay on my mechanics or I get a little out of whack," said Affeldt, who owns a 3.00 ERA in a team-high 11 appearances. "Some guys don't ever have to worry about it or think about it."
During Affeldt's session, he pictures at least three hitters whom he'll likely face in the game. The left-hander gives himself positive reinforcement by imagining that each pitch is perfectly executed.
"I believe muscle memory's important, and the mentality of making sure that your body feels like it already did something [before a game]," Affeldt said. "So when I get in that situation, I've already done it in my mind."
Affeldt explained that whipping a towel through the air taxes a pitcher less than throwing a ball -- "There are only so many bullets in our arm," he said -- yet provides sufficient heft.
"There's a little bit of resistance with a towel, but not a baseball-level of resistance," Affeldt said. "You're basically doing it with a lighter load."
Chris Haft is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.