Gerardo Parra homers again today (O's lead 6-2)

Orioles left-hander Wei-Yin Chen needed 22 pitches today to get through the first inning, the last 11 in Brett Lawrie's at-bat, but he managed to strand runners on the corners and keep the game scoreless.

It didn't stay that way for long.

Gerardo Parra homered for the second time in two games to give the Orioles a 1-0 lead in the bottom of the first.

Parra fouled off three straight pitches from Athletics starter Kendall Graveman - a changeup, sinker and cutter - before lining a slider into the right field seats.

Manager Buck Showalter anticipates having Matt Wieters in the lineup Monday night for the series finale. If so, Wieters will be facing confirmed starter Sonny Gray.

Showalter said Wieters should be ready to play after straining his right hamstring Tuesday night in Seattle. Wieters doesn't need to catch to avoid the disabled list.

"No, no," Showalter said. "Just making progress. He's worth waiting on.

"This is day four or five. Seven, eight, nine days, we'll wait. It's not hurting. We've got Steve (Clevenger) here. The roster works. You have (Ryan) Flaherty, guys who can play. Chris (Davis) can play two or three places.

"Stevie Clevenger can play a couple of other places, too. If you don't believe me, ask him."

Showalter noted that Steve Pearce had a setback down in Sarasota while rehabbing his strained oblique muscle.

"He came in a little, what was the word they used? It wasn't sore. Tight. A little tight," Showalter said.

"They decided to back off for a day or so. I haven't heard a report today."

Still think the Orioles invented Pearce's injury?

Pearce may not be ready to start an injury rehab assignment this week.

"We were hoping first part of the week, but we'll wait and see how the next day or two goes," Showalter said.

Gray has been pushed back to Monday's game due to back spasms. He's 12-4 with a 2.06 ERA in 23 starts this season, but he's 1-2 with a 7.04 ERA in three career starts against the Orioles, with 12 earned runs (13 total) in 15 1/3 innings. He's 0-2 with an 11.42 ERA in two starts at Camden Yards, with 11 runs and 12 hits in 8 2/3 innings.

Showalter joked that it must be a slow news day because reporters were asking him about September call-ups. He doesn't like to load up the clubhouse with new players.

"I'd like to get to the point where you can call up as many as you want, but you have to designate 25 for that three game series," he said.

Having extra relievers works to Showalter's advantage with the way he manages a bullpen.

"If we get people that can do their job," Showalter said. "I was talking to Ronny (Johnson) about that a little bit."

Update: The Orioles gave Oakland a run in the top of the second and scored four times in the bottom half to lead 5-1.

Marcus Semien was credited with a two-out double after Davis, Jonathan Schoop and Parra let his pop up drop in shallow right field. Davis made a late reach for it and missed. Semien scored on Sam Fuld's legit double.

Schoop and Steve Clevenger opened the bottom half with singles and they scored with two outs on Caleb Joseph's double. The Orioles are 36-5 when Joseph has an RBI and 17-2 when he collects two or more.

Joseph saved the inning. J.J. Hardy struck out and Henry Urrutia hit a chopper to the mound, with Schoop getting caught in a rundown, but Joseph delivered to break the tie.

The Orioles weren't done. Manny Machado followed with an RBI double and he scored on Parra's single.

Update II: Adam Jones homered into the Orioles' bullpen leading off the third, his 21st of the season, to expand the lead to 6-1.

Update III: Brett Lawrie led off the top of the fourth with a home run to reduce the lead to 6-2.