Mariners right-hander Hisashi Iwakuma has not pitched well since he overcame neck soreness to throw an eight-inning, one-run gem to beat the the Rangers, 5-1 at Safeco Field on June 15.
In two subsequent starts, the 33-year-old is 0-1 with a 10.00 ERA in nine innings. In that small but alarming span, opponents own a .405 batting average and a 1.098 OPS.
Iwakuma's chance to rebound comes Tuesday night against the last-place Astros at Minute Maid Park.
Iwakuma said the neck soreness was still present during his latest start, when he allowed five runs on eight hits and a walk against the Red Sox in a season-low four innings. The outing led to a 5-4 Mariners loss.
"I need to reflect on what I've done wrong and prepare for my next start," Iwakuma said afterward through interpreter Antony Suzuki. "I was just mislocating in critical situations, and they took advantage. I did feel it, but it's not affecting my pitching at all. I'm able to go through my routines, and I'm responsible for the last two starts."
Iwakuma (5-4, 3.48 ERA) threw a light bullpen on Saturday after not throwing bullpens the previous two weeks. It came three days after his most recent start -- not his usual routine of two days -- because the Mariners were off Thursday.
On Monday, manager Lloyd McClendon insisted his No. 2 starter was just fine.
"He gets an extra day this time, and that should freshen him up a little," McClendon said.
Iwakuma is 3-2 with a 2.72 ERA in six career starts against Houston, including 1-1 with a 5.27 ERA in two starts this year.
The Astros will counter with right-hander Jarred Cosart, who is 4-0 with a 2.25 ERA over his past four starts, allowing 26 hits and, more importantly, only six walks in 28 innings pitched in that span. He has walked two batters or fewer in each of his past six starts after struggling with his command early in the season.
Cosart did not downplay the importance of playing a division opponent.
"They're hot, we're hot. They know what we do, and we know what they do," he said. "It comes down to execution, and you have to execute your game plan or it could be a long day."
Mariners: Maurer to get longer look in 'pen
The Mariners chose to keep right-handed reliever Brandon Maurer and go with a seven-man bullpen after optioning outfielder Stefen Romero to Triple-A Tacoma, which leaves just three position players on the bench for now. But manager Lloyd McClendon said Maurer's impressive performance -- three scoreless innings with six strikeouts in his first two relief appearances -- warranted the move.
"There are a couple factors that played into it," McClendon said. "No. 1, our pitching has been our foundation, and this gives us a chance to protect it a little and shorten up ballgames. We all know offensively we're challenged a little, so it gives us a chance to shorten games when we can and protect guys and not overuse anybody. And this guy was pretty impressive coming out of the bullpen. It's very hard to ignore what he did two times coming out of the bullpen, so we'd like to see more of him."
Even without Romero, the Mariners still have five outfielders with Dustin Ackley, James Jones, Michael Saunders, Endy Chavez and Cole Gillespie, while utilityman Willie Bloomquist can also play there if needed.
"Bloomy can play all over the place, and that obviously gives you a little more flexibility," McClendon said. "Listen, it's not like we've had this tremendous bench that we've run through every game. That factored in as well. In the American League, you have a DH. You don't pinch-hit that much and use your bench that much. And we don't play the NL until Aug. 18, so it gives us a chance to give us a little more run with our pitching."
Astros: Showing signs of progress
The Astros are 21-21 since May 5, a .500 record that can be attributed in large part to their starting pitching.
Before Monday's 10-4 loss to the Mariners, Houston starters had given up 116 earned runs over 318 innings dating back to May 5. That 3.28 ERA was the best mark in the American League and third best in the Major Leagues during that span.
Houston starting pitchers entered Monday with a combined ERA of 3.78, good for fourth best in the AL and 11th in the Majors.
• When Cleveland's Josh Tomlin threw a one-hitter against the Mariners on Saturday and Felix Hernandez and Fernando Rodney returned the favor in Seattle's victory over the Indians on Sunday at Safeco Field, it was the first time since May 3-4, 1996, at Tiger Stadium that an American League park had seen back-to-back one hitters.
• After starting the season with a 1-5-1 record in their first seven series, the Mariners have gone 12-5-4 in series and won their past three entering this three-game set with the Astros. At 45-38, the Mariners are a season-best seven games above .500.
Adam Lewis is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.