Penny has had his ass handed to him in his last two starts. He did hold the Reds to just 1 run over 6 innings back on April 21st, but that was a different team, one that wasn't carrying a 6-game winning streak.
Arroyo is coming off of consecutive excellent starts. It's good that he is starting the series opener so that the LA nightlife hasn't gotten to him yet.
It'll be interesting to see how the Reds handle this West Coast trip given their past history perpetual suck in the Pacific Time Zone. They've lost their last 6 at Dodger Stadium, so they are due. No better time than tonight to win one.