The A's acquired Moll from the Rockies in exchange for a player to be named later or cash and optioned him to Triple-A Nashville on Wednesday.
Colorado effectively cut ties with its 2013 third-round pick last week, designating Moll for assignment, but the A's deemed Moll worthy of a 40-man spot. The lefty has struggled in the PCL this year, but he figures to get his first major-league opportunity in September as the A's evaluate for 2018.