Lopez was optioned to Triple-A Louisville on Sunday.
Lopez was promoted from Louisville on Wednesday and went 0-for-4 with two strikeouts in three appearances for the Reds. He'll return to the Triple-A level, where he has a .316/.406/.464 slash line with four homers, 17 doubles, 24 RBI, 42 runs, five stolen bases and a 29:17 BB:K in 229 plate appearances.