Lee signed a minor-league contract with the Rockies on Feb. 9.
Lee signed a minor-league contract with Oakland, which includes an invitation to spring training.
Lee cleared waivers Thursday and will head to Triple-A El Paso, Dennis Lin of the San Diego Union-Tribune reports.
Lee was designated for assignment by the Padres on Monday.
Lee allowed four runs (three earned) on eight hits and a walk during Friday's 14-12 win over Triple-A Fresno.
Lee was optioned to Triple-A El Paso on Sunday, Dennis Lin of the San Diego Union-Tribune reports.
Lee (1-0) held the Rockies scoreless over 5.1 innings in Coors Field on Wednesday, giving up just two hits along with four walks while striking out three in a 6-0 win.
Lee will be the starting pitcher for Wednesday's game against the Rockies.
Lee was recalled from Triple-A El Paso on Sunday, Jeff Sanders of the San Diego Union-Tribune reports.
Lee was optioned to Triple-A El Paso on Monday.