The demotion is thought to be temporary and he "definitely has a good shot" at regaining his rotation spot once another starter is needed, but manager Bob Melvin noted, "Nothing is promised to you in this game. He knows that. I talked to him about that."
"Obviously, it's not the desired spot you want to be in, not something that you want," Straily said. "But there are no guarantees in this game, so I'll go down there and compete and make sure I'm the first one on the list to come back up."
Straily, 4-2 with a 5.00 ERA in 12 starts this year, has a career-high three-game winning streak over his last seven starts, but has tossed fewer than five innings in each of his last two -- including Saturday, when he gave up two runs on six hits and three walks to the Mariners in just 3 1/3 innings.
"All these days off, they told me it was either keep me as a long guy in the bullpen," he said, "or send me down and keep me pitching."
"He's going to go down there and pitch like he would any other game," Melvin said, "and things will take care of itself."
If the A's have any qualms about bringing Straily back in July, top pitching prospect Sonny Gray could be considered. The righty is 7-4 with a 2.85 ERA and 90 strikeouts in 88 1/3 innings over 14 starts with the River Cats.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.