The right-hander tries to avoid losing three straight starts for the first time and lead the Mariners to a season high-tying fifth consecutive victory Wednesday against the Atlanta Braves.
Robinson Cano and John Buck each had three hits Tuesday as Seattle (30-28) won its first interleague game in four tries this season, 7-5 at Atlanta. The Mariners have totaled 17 runs in their last two games after averaging 3.5 in the previous eight.
Cano is batting .429 (24 for 56) during a 13-game road hitting streak, with the Mariners winning nine times.
Buck, who hit his first homer of the season, is batting .273 with four home runs and 11 RBIs in his last 13 games against the Braves (31-26).
"You play them enough, you're bound to get a few,'' said Buck, who faced Atlanta 12 times last season with the New York Mets.
Iwakuma (3-2, 3.09 ERA) allowed six runs and 20 hits in 30 2-3 innings to go 3-0 in his first four starts after missing the first month of the season because of a torn tendon on his finger. However, he has yielded nine runs - on four homers - and 17 hits over 13 innings of his last two. He gave up five of those runs in six innings of a 6-3 loss to Detroit on Friday.
"I didn't see the finish to his pitches that he usually has," manager Lloyd McClendon told MLB's official website. "He probably had a little bit of tired arm, not having a spring training and going as deep in ballgames as he's gone. It's probably something that's normal and something to be expected."
Iwakuma allowed 10 runs over 14 2-3 innings while going 0-1 in his first two interleague starts last season before he yielded three hits in seven scoreless innings of a 2-1, 10-inning loss at St. Louis on Sept. 13.
He'll get his first look at the Braves, who were coming off a three-game road sweep of Miami before blowing a 4-0 first-inning lead Tuesday to drop to 0-5 against AL opponents this year.
''We let them hang around and they came back and they got the big hits,'' Braves manager Fredi Gonzalez said. ''You've got to give them the credit.''
Atlanta starting pitchers have a 6.19 ERA during a three-game home slide.
Since giving up six runs and 11 hits in 4 1-3 innings of a 7-1 loss to St. Louis in his second start of the season May 7, Atlanta's Mike Minor (2-3, 3.41) is 2-1 with a 2.03 ERA in the last four. The left-hander gave up a run in seven innings while not receiving a decision in Thursday's 4-3 loss at Boston.
This will be Minor's first appearance against the Mariners.
Buck's only hit in 14 at-bats versus Minor left the park. Cano is 0 for 5 against him.
Atlanta's Evan Gattis hit a three-run shot for his second homer in as many games. He's batting .381 (8 for 21) with four home runs and nine RBIs in his last six contests.