OAKLAND -- The A's have two new additions to the rotation, at least for their four-game series against the Orioles, in Ross Detwiler and Andrew Triggs.
Detwiler will start Wednesday and Triggs Thursday, filling two empty spots as the A's look to replace Jesse Hahn and Sonny Gray, who were placed on the 15-day disabled list within the past week. A's manager Bob Melvin didn't commit to Detwiler or Triggs remaining in the rotation beyond their respective starts.
Gray underwent an MRI on Monday on his strained right forearm and won't require surgery. However, there's no timetable for his return.

Detwiler, 30, was acquired in a trade with the Indians on July 17 and assigned to Triple-A Nashville. He's 4-0 with a 3.86 ERA in four games (three starts) and has 24 strikeouts in 23 1/3 innings. A first-round pick of the Nationals in the 2007 MLB Draft, the lefty has experience as a starter and reliever in the Majors, posting a 4.21 ERA in 534 innings with Washington, Texas, Atlanta and Cleveland.
Oakland has used Triggs primarily as a long reliever in eight stints in the Majors this seson, but the righty made one start in what was deemed a "bullpen day," allowing one run in three innings against the Angels on June 18. He has a 5.35 ERA in 19 appearances.
The A's will need to make a roster move to add Detwiler to the 40-man roster. They opted against calling on a Minor League arm already on the 40-man roster, including Daniel Mengden, who made nine starts with Oakland this year.
"We didn't want to bring Daniel Mengden back right now," Melvin said. "We felt like he needed a little bit of a break. We cut down on his pitches in Triple-A right now."
Melvin said the team also considered Raúl Alcántara and Jharel Cotton, who are pitching at Triple-A. Alcantara's 4-0 with a 0.70 ERA in four starts since being called up to Nashville July 20, and Cotton allowed one run in six innings Aug. 4 in his first start since being acquired from the Dodgers in a trade for Rich Hill and Josh Reddick.
"I think everything was considered," Melvin said. "We'll see how the guys we have going forward, whether it's Sonny or Jesse, how they do. I think we still feel like some of these guys need to develop a little bit, whether it's Alcantara you're talking about it. Cotton just got here, he was another consideration. We'll see where we go next time around."
Worth noting
• Second baseman Jed Lowrie is awaiting MRI results on his ailing left big toe. Lowrie was placed on the DL on Friday, and said Monday he may soon see a foot specialist.