The veteran also enters off his shortest outing of the season as he tries to help the Mariners hand the visiting Astros a sixth straight loss Tuesday night.
Harang (2-6, 6.70 ERA) has beaten the Astros 13 times and has posted a 2.64 ERA in winning his last five starts against them.
The right-hander, however, has failed to get through the fifth inning four times this season. The latest such outing was Thursday as he pitched two scoreless innings before retiring one batter and yielding six runs in the third in a 6-1 defeat to the Yankees.
"They started knocking the ball around and we had to get him out of there," manager Eric Wedge said. "He wasn't making any pitches and they weren't missing them. It happened pretty quick."
Harang seemed to disagree with his manager's assessment, saying he made one mistake.
He doesn't have much experience against Houston's hitters, with Ronny Cedeno (7 for 24) the only Astro with more than six at-bats against him.
Houston starter Bud Norris (5-5, 3.43) will face a Seattle lineup that features some players playing through pain.
Kendrys Morales, battling back trouble, returned to first base in Monday's 3-2 victory that opened this three-game set after serving as the designated hitter Sunday.
One name Wedge will continue to pencil in is Kyle Seager, who went 0 for 5 on Monday. Seager batted .373 during a 13-game hit streak that ended.
It's well documented that Norris has been a different pitcher at home than on the road, going 7-3 with a 1.94 ERA in Houston over the last two seasons and 5-15 with a 6.94 ERA elsewhere.
The right-hander is 1-1 with a 1.73 ERA over his last four starts. His lone career outing against the Mariners (28-37) was his 3-2 home victory April 23 in which he surrendered one run in five innings.
Houston second baseman Jose Altuve owns a career-high 11-game hitting streak, although he's batting just .277 during that run.
Chris Carter, however, is in a 2-for-17 slide and Matt Dominguez a 3-for-17 slump. Those hitters lead Houston (22-43) with 33 and 32 RBIs, respectively.
The Astros enter Tuesday looking to avoid their third six-game losing streak.
"You just have to keep plugging away," manager Bo Porter said. "It's like we talk about, the break points, and right now we're losing those critical break points and the other teams are capitalizing."
Carter went 0 for 3 on Monday after going 11 for 26 in the first six games of the season series. Dominguez was 0 for 4 after he was 9 for 22.
Shortstop Marwin Gonzalez is 8 for 15 with six runs scored against the Mariners this season.