OAKLAND, Calif. – ­­­­The Oakland A’s optioned right-handed pitcher Daulton Jefferies to Triple-A Las Vegas, the club announced today. The A’s also reassigned left-handed pitcher Donnie Hart and right-handed pitchers Ben Bracewell, Parker Dunshee, Ian Gardeck, Brian Howard and Zach Lee to their minor league camp. Oakland now has 51 players on the active roster, which includes 36 players on the 40-man roster and 15 non-roster invitees.