While things went right for Oakland in the first half of that stretch, they haven't since.
Parker (6-6, 3.79 ERA) is 4-0 with a 2.17 ERA over his last 10 starts with an opponent batting average of .175 - the best in the league since May 28.
Oakland (61-43) won the first five starts of this stellar stretch by Parker, but has totaled 12 runs in losing the next five. The right-hander's ERA is 2.32 and opponent batting average is .180 during his winless run.
The Athletics have won both of his starts against Los Angeles this year, with Parker going 1-0 with a 4.82 ERA.
That's because Pujols returned to Los Angeles on Saturday morning for further testing on his ailing left foot. The slugger has been dealing with plantar fasciitis all season, re-injuring his foot running to first base after singling in the ninth inning in Friday's 6-4 loss.
The Angels (48-54) opened this four-game set Thursday with an 8-3 victory before the Athletics responded with strong starts by Bartolo Colon and Tommy Milone to take the next two games.
Colon won his 14th game with six innings Friday before Milone gave up one run over seven in Saturday's 3-1 victory.
Los Angeles took the lead Saturday on Hamilton's second-inning homer. Oakland did all of its scoring in the seventh, with Derek Norris' two-run pinch-hit homer putting the home team up by one.
"That's just the way we play baseball,'' Norris said. "There's no one guy like a (Miguel) Cabrera or a Chris Davis. We have a group of guys who can put together things."
Norris rudely greeted reliever Scott Downs, who allowed his first run in 30 appearances, one short of tying the Angels club record. The last homer allowed by Downs was Sept. 25 by Seattle's Justin Smoak.
"I can't remember the last time Downs gave up a home run," manager Mike Scioscia said. "You like the matchup with his sinker and hopefully he can get the double play ball."
Scioscia will give the ball to Tommy Hanson (4-2, 4.75), who yielded one run over 5 1-3 innings and did not get a decision in Tuesday's 10-3 defeat to Minnesota - his first start since June 20 after being on the disabled list with a strained right forearm.
The right-hander's lone career outing against Oakland was a 10-8, 19-inning loss April 29. He allowed two runs in six innings.
Trout is 5 for 12 in this series and has hit safely in nine straight games against the A's with a .342 average and 10 RBIs.
Jed Lowrie is 5 for 12 with five RBIs for Oakland in this series while slugger Yoenis Cespedes is 0 for 9 with five strikeouts.