Bumgarner retired the first 10 Reds before Brandon Phillips singled in the fourth. That was the only hit allowed by Bumgarner, who walked none.
Andres Torres, Freddy Sanchez and Cody Ross homered against Arroyo in a four-run third inning.
Edinson Volquez, the Reds' opening-day starter, made his first spring appearance after clearing up a visa problems in the Dominican Republic. Set to go three innings, he reached his pitch count after 2 1-3 innings.
Edgar Renteria, the World Series MVP last year with San Francisco, played for Cincinnati. Giants fans gave him a standing ovation and chanted ``MVP!''