SEATTLE -- After veteran right-hander Hisashi Iwakuma had a rough two-inning rehab start in Triple-A Tacoma on Monday night, the Mariners will have him make at least one more Minor League start instead of rejoining the rotation on Saturday as originally planned.
Manager Scott Servais has already announced that Felix Hernandez will return from the disabled list and pitch Friday's series opener with the Astros, but Saturday's starter now is yet to be decided as the club debates whether to go with rookie Sam Gaviglio or veteran Christian Bergman.
Iwakuma's next outing hasn't been determined yet, but he'll be given an extra day or two between starts, which likely means taking the mound again on Saturday or Sunday after allowing four hits and four runs with a pair of walks in a 49-pitch outing against Salt Lake on Monday.
"Obviously it didn't go the way either Kuma or we were hoping it would," Servais said. "He's definitely going to have at least one more rehab start. We'll do the right thing and hopefully he bounces back from it. Health-wise, it was just OK. The ball wasn't really doing a whole lot coming out. It sounds like the split-finger was OK, but we need to give him a little more time. He's not ready to go out in a Major League game right now and help us."
The 36-year-old Iwakuma wasn't arguing with that decision. He was taken out after needing 32 pitches to get through the second inning of a game where the Mariners had hoped to push him to 5-6 innings and 75 pitches following a much-sharper outing five days earlier for Class A Modesto.
"Obviously it was below average," Iwakuma said of his performance. "If it was out of 100, I'd say it was about 40 percent. The ball wasn't coming out very good. I didn't feel too good or have very good command. But there were some good signs and I need to keep that in mind and make adjustments moving forward."
Speaking through interpreter Antony Suzuki, Iwakuma said he felt some tightness during the lengthy second inning and had some expected day-after soreness on Tuesday. But health doesn't seem to be the concern with his shoulder now as much as regaining the quality of his pitches after being sidelined nearly seven weeks.
"I felt better in general," he said, compared to his previous outing in Modesto. "The results were not the same, but obviously when you face Triple-A hitters, the quality of the hitters gets better. That second inning, throwing 32 pitches, it did put a lot of stress on my shoulder. Even then, I had a few good pitches in that inning and I need to work on that and stay positive about making the next step."
Iwakuma has been sidelined since May 3 after going 0-2 with a 4.35 ERA in his first six starts.
With Hernandez set to return, either Bergman or Gaviglio is about to lose his position in the rotation. Servais indicated whoever doesn't remain in the mix would likely continue starting for Tacoma in order to remain stretched out if needed.
The club also has two off days next week -- on Monday and Thursday -- so that provides more flexibility and the likelihood that Yovani Gallardo will have his next outing pushed back after he pitches this Thursday's series finale with the Tigers.