The Mariners seek a rare sweep of the slumping Angels as the teams meet Thursday night in Seattle.
With a 3-0 victory Wednesday, Seattle (18-24) handed Weaver his fourth straight loss, again denying him a chance to become the first seven-game winner in the majors.
"I've been feeling my swing come around, driving the ball a little bit more," said Cust, who's batting a season-high .225 and appears well on his way to a fifth season with at least 127 strikeouts.
Seattle is now in position for its first sweep of any length against the Angels (22-22) since June 9-11, 2006, in Anaheim. The Mariners haven't posted a sweep of Los Angeles at Safeco Field since Sept. 12-14, 2005.
Bobby Abreu had two hits Wednesday for the Angels, losers of four straight and six of seven. Los Angeles has not been below .500 since it was 3-4 on April 8.
To try and avoid that fate, Haren (4-2, 1.93 ERA) hopes to end a winless stretch that's lasted more than a month.
Haren was 4-0 with a 1.16 ERA in five appearances through April 17, including a victory during his first relief appearance in 6 1/2 years. In his last five starts, the right-hander is 0-2 with a 2.62 ERA.
Los Angeles has scored either one run or none for him in three of those games.
Haren has failed to get decisions in his last two starts. On Saturday against Texas, he was reached for two runs and six hits in 7 2-3 innings, and the Angels pushed across a run in the top of the ninth for a 3-2 win.
"That's the story of my life. It's no big deal. We won the game," Haren said. "When you lose the game, that's hard to handle. But we won the game so I'll sleep good (Saturday night)."
Haren scattered three hits over seven innings of the Angels' 3-0 victory over the Mariners on Sept. 12, improving to 7-4 with a 2.55 ERA in 14 career starts against Seattle.
Ichiro Suzuki had one hit Wednesday, and is batting .313 during a seven-game hitting streak versus Los Angeles. Suzuki has 13 hits off Haren in 48 career at-bats.
Following his longest outing of 2011, Doug Fister (2-4, 3.22) will start for Seattle.
The right-hander went eight innings against major league-leading Cleveland on Friday, allowing two solo homers among four hits. Brandon League, though, gave up Travis Hafner's three-run homer with two outs in the bottom of the ninth as the Mariners fell 5-4.
Fister's only win in three career starts against the Angels came Sept. 1, 2009, in Seattle. He yielded one run and five hits through 7 1-3 innings of the 2-1 victory.