With Hector Noesi sent down to Triple-A Tacoma on Thursday and rookie Erasmo Ramirez on the 15-day disabled list with a sore elbow, Iwakuma will take one of the starting slots. Iwakuma made a spot start last week against the Orioles and threw five innings of three-run ball.
Wedge said Ramirez wouldn't likely be ready to pitch the first time through the rotation after the break, so another move likely would be coming.
Blake Beavan is 2-0 with a 2.52 ERA in four starts since being sent down to Tacoma, so he could be a possibility. Noesi would also be eligible to return by the time the Mariners need a fifth starter after the break, but Wedge sounded as if they'd like him to work on some things first.
"He has to just be more consistent, focus better from pitch to pitch, finish off hitters," Wedge said. "I'd like to see him have a little more intensity on the mound. With that will come the focus and having a purpose with every pitch and executing pitches. It's just being able to throw 100 pitches and get the most out of each and every one. I like his delivery, I like his stuff."
Wedge said some of the rotation issues after the break could depend on Felix Hernandez's pitch count in the All-Star Game on Tuesday. The Mariners have had discussions with Rangers manager Ron Washington about Hernandez's usage, but Wedge wouldn't discuss specifics.
In previous years, pitchers who threw on the Sunday before the All-Star Game weren't allowed to pitch in the Tuesday game. This year, they are allowed to do so, but teams have the chance to set parameters on how they'll be used.