Guthrie allowed two runs and six hits while he was on the mound, with four walks and five strikeouts. He threw 111 pitches, which forced manager Buck Showalter to call upon relievers Clay Rapada and Jim Johnson in the sixth inning.
Rapada walked Joey Votto to load the bases, and Johnson walked Jonny Gomes and Fred Lewis to force in two runs and complete Guthrie's line. Guthrie is charged with four runs.
Johnson clearly was upset with Alan Porter's strike zone. Porter squeezed him so tight, he left finger prints.
The last pitch to Lewis was clearly a strike.
An Orioles starter has failed to get through the sixth inning in eight of the last 10 games.
Brandon Phillips homered off Guthrie in the fifth, and the Reds followed with back-to-back walks. Guthrie retired the next two batters to end the inning, but Chris Heisley's two-out single in the sixth scored Miguel Cairo.
Guthrie walked Phillips, and Showalter came out of the dugout.
Left-handers were batting .118 against Rapada before today, but he couldn't retire Votto. They're 4-for-34 with three walks and 12 strikeouts.
The Orioles might regret wasting a golden scoring opportunity in the fifth. Nick Markakis singled and Adam Jones doubled to put runners on second and third with no outs. Vladimir Guerrero popped up and Derrek Lee grounded into a force at home. Luke Scott walked to load the bases, but Mark Reynolds fouled out.
Instant update: Nick Markakis' third hit, a two-out single into right field in the bottom of the sixth, scored Blake Davis and increased the Orioles' lead to 6-4. Davis is 2-for-2 with a walk and two runs scored. Markakis is 3-for-4 with two RBIs, raising his average to .277.