There was no disappointment either.
"Disappointment comes from lack of preparation and lack of work," he said. "I would like to pitch better, but I've done everything I can."
So Guthrie heads to the bullpen and Kris Medlen joins the rotation and will start Monday.
But as Guthrie and his 5.65 ERA head to the bullpen, he doesn't expect to get much work in long relief.
"They don't need long guys here," he said. "Starting pitchers go deep. Kris Medlen and Chris Young have thrown like five times in two months."
So what will his mental approach be?
"I just prepare, and if needed, be the best ready that I can be," Guthrie said. "That's how uncomplicated baseball can be."
Guthrie, who could be a free agent after this season if the Royals decline a mutual option, said he isn't sure why he has struggled so much this year.
"I don't believe there's anything I've been asked to try that I haven't tried," he said. "The main thing is that my ERA in my final inning each outing is probably 30, but around the rest of the innings, I've been my normal self. I don't know why."
Jeffrey Flanagan is a reporter for MLB.com. Follow him on Twitter at @FlannyMLB. This story was not subject to the approval of Major League Baseball or its clubs.