Halama is making his second straight start in place of injured left-hander Mark Mulder, who led the team with 15 wins before a broken leg bone near his hip ended his season last week.
Halama, used mostly as a reliever this season, didn’t receive a decision on Saturday, but did help the A’s to an 11-5 win at Toronto. He gave up three runs and six hits over four innings.
The left-hander is 2-4 with a 4.66 ERA in 11 starts this season, but is 2-1 with a 3.19 ERA at home. He has also pitched well in his career against Baltimore, going 2-2 with a 2.47 ERA. Halama started against the Orioles on July 12, but did not receive a decision in Oakland’s 5-3 win, yielding one run and six hits over five innings.
The A’s snapped a first-place tie with Seattle with Wednesday’s 6-2 win over Baltimore. The Mariners lost 8-4 to visiting Tampa Bay, slipping out of the top spot in the division for the first time since April 14.
Oakland has won five straight and nine of 11 to move to a season-high 23 games above .500.
Miguel Tejada hit two homers and drove in three runs for Oakland on Wednesday. The reigning AL MVP is batting .529 (18-for-31) during an eight-game hitting streak with six homers and 13 RBIs.
The Orioles lost their fourth straight following a four-game winning streak.
STANDINGS: Orioles - 4th place, 19 1/2 GB, AL East. Athletics - 1st place, AL West.
ORIOLES PROBABLE STARTER: Rodrigo Lopez (6-8, 5.45 ERA). Lopez snapped a personal two-game losing streak Saturday, pitching a six-hitter against Mike Mussina and the New York Yankees at Yankee Stadium. The Mexican right-hander struck out a career-high 10 in his second complete game this season and third of his career. He has won three of his last five decisions. Lopez, 1-5 with a 6.26 ERA on the road this season, is 1-2 with a 3.46 ERA in four career starts against Oakland.
ATHLETICS PROBABLE STARTER: Halama (2-4, 4.05 ERA). Halama has a 3.79 ERA in nine games, including one start, since the All-Star break. He went 2-4 with a 4.12 in the first half.
OFFENSIVE LEADERS: Orioles - Jeff Conine, .291 avg., and 75 runs; Tony Batista, 22 HRs; Jay Gibbons, 89 RBIs; Brian Roberts, 20 SBs. Athletics - Eric Chavez, .277 avg. and 24 HRs; Miguel Tejada, 88 RBIs and 79 runs; Eric Byrnes, 9 SBs.
SEASON SERIES: Athletics, 5-0.
STREAKS AND NOTES: Orioles - The Orioles are 11-16 in August after going 15-10 in July. … The Orioles are 117-100 all-time at Oakland. … LF Larry Bigbie had his career-high seven-game hitting streak snapped Wednesday. … OF Luis Matos got the night off Wednesday after getting hit on the left wrist in the 12th inning of Baltimore’s 2-1 loss Tuesday. Athletics - SS Tejada, who recorded his seventh career multihomer game Wednesday, is batting ..364 (4-for-11) career against RHP Lopez with a homer. … 3B Chavez, who homered Wednesday, is hitting .344 (11-for-32) over his last eight games. … Oakland has an AL-best 3.53 ERA.
ROAD/HOME RECORDS: Orioles - 28-39 on the road; Athletics - 46-21 at home.
INJURIES: Orioles - 1B David Segui (wrist), 15-day DL; OF Melvin Mora (hand), 15-day DL; RHP Kurt Ainsworth (shoulder), 15-day DL; LHP Omar Daal (rotator cuff), 15-day DL; LHP Erik Bedard (elbow), 60-day DL; RHP Scott Erickson (shoulder), 60-day DL; RHP Willis Roberts (elbow), 60-day DL; 2B Jerry Hairston Jr. (foot), 60-day DL; OF Albert Belle (hip), 60-day DL; OF Marty Cordova (elbow), 60-day DL. Athletics - OF Jermaine Dye (shoulder), 15-day DL; LHP Micah Bowie (elbow), 15-day DL; LHP Mulder (hip), 15-day DL.