On Friday night in the opening game of a three-game series against San Diego, Arroyo was the latest example, allowing eight earned runs on eight hits in three-plus innings as the Padres rolled to a 10-4 victory over the Reds before 15,183 fans at Great American Ball Park.
San Diego extended its winning streak to seven.
Arroyo -- who was named Friday's starter in place of Johnny Cueto who was given an extra day's rest -- conveyed a sense of urgency following the game.
"This early in the season you usually feel the pitchers have the advantage coming out of camp," Arroyo said. "We've got to turn the corner, somehow, some way."
Friday's outing was Arroyo's shortest since he went just three-plus innings in a 15-3 loss to Milwaukee on May 9, 2009 at Great American Ball Park. He allowed nine earned runs in that contest including Ryan Braun's grand slam.
"We've covered this before," said Reds manager Dusty Baker of Arroyo. "He'll go through a few starts where he struggles, then he'll reel off seven or eight in a row. I hope this is the end of the bad streak."
Arroyo (0-2) threw 88 pitches and couldn't get through the fourth inning.
"I just haven't gotten it done," Arroyo said. "I just got beat, man. Having those big innings kills you, no matter how the game's going."
Matt Stairs, who was inserted into the starting lineup by Padres manager Bud Black when the Reds announced Arroyo as the starter, had a two-run double to right in the second to put the Padres ahead 2-0.
Tony Gwynn followed with his first home run of the season to make the score 4-0.
San Diego scored six runs in the fourth, the most allowed by the Reds in one inning this season. The Reds have given up at least four runs in their past 11 games.
Arroyo, who faced four batters in the fourth inning, walked Padres starting pitcher Kevin Correia, who was attempting to sacrifice bunt, to load the bases with no outs.
With the infield in, Everth Cabrera lined a single past Joey Votto's outstretched glove to drive in two runs, putting the Padres ahead, 6-0.
Adrian Gonzalez then launched the first pitch from Micah Owings 395 feet into the right-field seats for his second career grand slam, making the score 10-0.
His last grand slam came on Oct. 1, 2007, at Colorado.
Gonzalez has homered in four of his past five games at Great American Ball Park.
That proved to be more than enough offensive support for Correia, who gave up just two earned runs on three hits in 5 2/3 innings.
Correia (3-1) held the Reds hitless until Ryan Hanigan doubled to begin the bottom of the sixth.
"For their guy to be throwing as well as he was, and for me to give up four or five runs early is too much to come back from," said Arroyo.
The Reds got on the board in the sixth when Hanigan doubled and scored on Orlando Cabrera's sacrifice fly.
Brandon Phillips' RBI single later in the inning made the score 10-2.
Hanigan was among the Reds' lone bright spots, going 2-for-3 with a double and an RBI.
Right-hander Carlos Fisher made his season debut for the Reds, allowing one hit and striking out two in an inning.
Paul Janish came off the bench to go 2-for-2 with a double and an RBI.
"We still have a chance to win the series -- two out of three," said Baker. "This is one that we just need to put behind us."