Jeffress signed a contract with a $1.55 million signing bonus in 2006, but has twice been suspended for testing positive for "a drug of abuse," and currently is serving a 100-game suspension in the minor leagues. His repertoire features a fastball that tops in the mid-90s and a hard-breaking slider. He is 20-21 with a 4.20 ERA in 64 minor-league games. On August 30 2007, Jeffress was suspended for fifty games after testing positive for "a drug of abuse." On June 29 2009, Jeffress was suspended for one-hundred games after testing positive for "a drug of abuse."