New York YankeesEdit
Clippard was drafted in the 9th round of the 2003 MLB Draft by the New York Yankees out of J. W. Mitchell High School. He played ball for the Central Florida Renegades Connie Mack team in Florida when he was drafted.
From 2003-2006, in the minor leagues, he averaged 7.5 hits, 2 walks, and 10 strikeouts per 9 innings for Yankees' farm teams. While playing for the Trenton Thunder in 2006, Clippard threw the franchise's first no-hitter.
Clippard was called up from the Yankees minor league team the Scranton/Wilkes-Barre Yankees on May 20, 2007, and made his debut that day. It was an interleague game against the New York Mets, and he pitched 6 innings, giving up 1 run off the bat of David Wright and 3 hits. He struck out his first major league batter José Reyes on three pitches in the first inning. He recorded his first career hit in his second at-bat off Mets pitcher Scott Schoeneweis, a double to right center in the 6th inning.
Clippard was traded on December 4, 2007, to the Washington Nationals for relief pitcher Jonathan Albaladejo.  He pitched his first game for the Nationals on June 9, 2008, after Odalis Pérez was placed on the 15-day disabled list. He is now the Nationals setup-man who pitches in the 8th inning.