BALTIMORE -- The Baltimore Orioles will try to improve their playoff chances with a pivotal three-game series against the Oakland A's beginning Monday at Camden Yards.

Baltimore didn't help its cause over the weekend by losing two of three games to the Los Angeles Angels, who are tied for the second AL wild-card position. The Orioles are four games back.

Orioles manager Buck Showalter said his team needs to quickly regroup and focus on Oakland. The Orioles (60-65) and A's (54-70) split a four-game series last week at Oakland Coliseum.

"You'd have liked to win the (Angels) series," Showalter said. "We'd have liked to win all three. We had a good opportunity, but they pitched a little bit better than we did.

"The competition is us. It's us playing better regardless of who you're playing. Our competition is Oakland now, and it's us. There's opportunity there for us. We'd like to win."

Orioles left-hander Wade Miley (6-10, 5.21 ERA) gets the start Monday. He has battled his command much of the season, and as a result, he has struggled to go deep into games. Miley has completed at least six innings just twice in his past 14 starts.

In his last outing Tuesday against the Seattle Mariners, Miley allowed three runs and five hits with three walks and four strikeouts in just 4 2/3 innings.

Miley has been effective in four career starts against the A's, going 3-1 with a 1.33 ERA. He also managed one of his best performances of the season Aug. 10 when he held the A's to one unearned run over seven innings.

Chris Smith (0-2, 5.26 ERA) takes the mound for Oakland in the opener. He has struggled over six starts this season, allowing more than three runs in three of his past four outings. Smith took the loss in his only career start against Baltimore when he allowed five runs and seven hits in six innings Aug. 10.

Oakland avoided a three-game sweep in Houston with a 3-2 victory Sunday. The A's will face another stern challenge against Baltimore's powerful lineup. However, manager Bob Melvin was encouraged by his rotation over the weekend, and he hopes that can carry over to the series against the Orioles.

"Going in, it wasn't great, and I know (the Astros are) not swinging the bats the way they have most of the season," Melvin said. "But they always present challenges, and late in games, they're always good. It's good to get three good starts. It seems there is some momentum that builds amongst the starters."

Baltimore got a boost Sunday when Chris Davis was able to get back in the lineup after being sidelined the previous two games because of a virus. Davis, who was fully recovered from the illness, hit his 19th homer Sunday in the Orioles' 5-4 loss to the Angels.

Davis should be available for all three games against Oakland. He is looking for the team to find some consistency.

"I think there's just been games that we've let slip away, some games we really haven't been able to close out whether it's scoring a run, whether it's tacking on a few runs to give us some breathing room," Davis said. "I think what's going to define us this year is whether or not we can make that push and start winning some of those games."