The A's have stood at the top of the American League West for much of the 2014 season, but the Angels are right behind them heading into a three-game series in Oakland starting Friday.
The Angels lost two of three to the A's back on April 14-16, but every game was decided by one run and two of them went extra innings with both of the Angels' losses the result of a bullpen meltdown -- first Ernesto Frieri, then Joe Smith. The Angels went 8-11 against Oakland last year.
After going 78-84 in 2013, the Angels appear to pose a bigger threat to the A's division-championship hopes this year.
"They're a good team," A's manager Bob Melvin said. "We saw them early in the season, they were swinging the bats well then, and they continue to swing the bats well. Better pitching now, not only in the bullpen but in the rotation, and some healthy players. Very good team."
Left-hander Drew Pomeranz, one of several pleasant surprises in the A's rotation, will get the nod in Friday's series opener. Pomeranz began the season in the bullpen, but was thrust into a starting role earlier this month.
In four starts, he is 3-1 with a 0.95 ERA. He surrendered his first two runs as a starter in his most recent outing in Toronto, lasting just four innings while taking the loss.
Pomeranz is fairly familiar with the Angels' high-powered lineup, having pitched 4 1/3 innings against them out of the 'pen in April.
"I threw pretty well," Pomeranz said. "[The key was] just staying in good counts, locating my fastball and using my curveball when I need to."
Garrett Richards, who gave up five runs in seven innings in his last start against the A's, will get the start for the Angels, and is hoping to be more effective this time.
"Just mixing pitches a little bit better. Being more cautious of throwing better quality strikes. Just getting ahead of guys," Richards said. "I think that last start I kind of fell behind on some counts. They hit some good pitches.
"When you play the teams in your division over and over again, guys start making adjustments, and that's when you have to start making adjustments."
A series win would push the Angels into first place in the division, in addition to topping one of the league's most dominant teams.
"They've had the same payroll for years. They just keep piecing things together. It just seems like it's somebody different every day. Whether it's [Josh] Donaldson or [Josh] Reddick or [Brandon] Moss or Derrick Norris, who's hitting a million right now, they truly don't believe they're out of a ballgame," said former A's outfielder Collin Cowgill. "Their bullpen is good enough to keep them in games, their starters get them through seven. Everything's clicking for them."
A's: Cook closing in on return
Reliever Ryan Cook appears likely to return soon from a right forearm strain that has kept him out since May 7.
The 2012 All-Star threw a pain-free bullpen session on Thursday, and Melvin said he may need just one Minor League rehab appearance before making his return. That appearance will likely occur on Saturday.
"Hopefully all goes well and then I just come back," Cook said Thursday.
Cook also missed the first week of the season with right shoulder tendinitis, but he said he feels significantly better now than he did after coming back from the shoulder injury.
The right-hander has a 2.92 ERA in 12 appearances this season.
Angels: Hamilton back on track
Barring an unforeseen setback, Josh Hamilton is slated to restart his rehab assignment with Triple-A Salt Lake on Friday and Angels manager Mike Scioscia is confident his cleanup hitter will return to the lineup before the road trip ends in Houston on June 5.
Hamilton was jammed badly in his first rehab game on May 22, then was scratched from the lineup on Friday and Saturday before being diagnosed with a bone bruise on his surgically repaired left thumb on Monday.
By Wednesday, he was hitting in the cage again. Prior to Thursday's game, he hit on the field without the protective splint that was bothering him upon contact.
• The A's and Angels ranked second and fourth in the AL in home runs, respectively, after Oakland's 5-4 loss against the Tigers on Thursday. Oakland has hit 60; Los Angeles has hit 57.
• The Angels have dropped 15 of 22 games to the A's at Angel Stadium, but have won 10 of their last 16 in Oakland.
• The Angels will face lefties in their first two games in Oakland. Since May 3, the Angels have faced a left-handed starter in 12 of 24 games. They're 13-8 against lefty starters this year.
Grace Raynor is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.