Cincinnati Reds right-hander Riley O'Brien allowed two runs over 1 1/3 innings in a 7-1 loss to the Chicago White Sox on Tuesday. O'Brien struck out two and walked three while allowing two homers in the loss. The rookie was making his MLB debut but he didn't stick around for very long, throwing just 22 of 42 pitches for strikes. O'Brien posted a 4.55 ERA and 121 strikeouts over 112 2/3 innings at Triple-A Louisville this year.