Iwakuma went 4-0 against the Angels last season and has baffled hitters in 2013 heading into Sunday's contest, which also features Jason Vargas' return to Safeco Field to face his former team.The lack of production from Pujols and Trout has been a theme in the first month for Los Angeles (9-14). Pujols is hitting .256, Trout is at .274 and they are being pitched to very carefully, combining for as many walks (25) as RBIs.Seattle (10-16) has taken two of three in this series, with Pujols going 2 for 11 with two RBIs and no walks while Trout is 3 for 10 with no runs scored and one RBI. Trout led the majors with 129 runs in 2012.Neither has fared well against Iwakuma (2-1, 1.99 ERA). Pujols has two doubles and no walks in 13 at-bats and Trout is 2 for 12 with one walk and three strikeouts.Iwakuma posted a 1.37 ERA in winning all four starts against the Angels last season, with 13 1/3 scoreless innings in two at home. Los Angeles batted .227 with one homer, 22 strikeouts and three walks against him in 2012.The Japanese right-hander struck out a season-high 11 and allowed three runs in Tuesday's 3-2 defeat at Houston -- his first loss in eight outings. He has been bothered by a blister on his throwing hand, although opponents are batting .164 against him."It's still an issue," manager Eric Wedge told the Mariners' official website. "We'll have to make his next start on regular rest, then after that we'll have an opportunity to maybe give him a couple days, working with the off days."Vargas (0-2, 5.82) was traded from Seattle to Los Angeles in the deal for Kendrys Morales as he makes his first start against the Mariners -- the only team he has never faced. He went 36-42 with a 4.09 ERA over his last four seasons for Seattle, going 14-11 with a 3.85 ERA in 2012.The left-hander said he was surprised to be dealt."I thought that I was going to be a part of it, but they had other plans," he told the Angels' official website. "And baseball changes quick, man. To be able to be a part of this (with Los Angeles), you couldn't ask for a better situation. Things happen the way they happen."Vargas turned in his longest outing of the season Tuesday, giving up three runs over seven innings in a 5-4, 11-inning victory over Texas.It's not surprising that the Seattle hitter he has faced the most is Morales, who is 5 for 12 with two homers against him.Morales started the first two games of this series before delivering a go-ahead, pinch-hit RBI single in the seventh inning of Saturday's 3-2 victory."It was a matter of having Kendrys Morales on the bench," Wedge said.The Mariners are trying to capture a series for the first time in 2013.