The Athletics designated Hartlieb for assignment Friday.
Both Hartlieb and Matt Krook were DFA'd by the Athletics in order to make room on the 40-man roster for Jose Suarez (paternity) and Mark Leiter (hip). Hartlieb was called up from Triple-A Las Vegas on June 20 and appeared in four major-league games for the A's, allowing five runs on 11 hits and three walks while striking out three across 8.2 innings. Hartlieb will have the opportunity to explore his options if he clears waivers.