"It's the same as always," McClendon said of his thinking. "Every chance I get to give them an extra day, I'm going to do it. I think we've done OK with it. Last time I checked, we had the best pitching in the American League. So why break something that's not broken? Keep doing it. Keep resting them. I want to protect them. … It had nothing to do with Toronto."
The Mariners stayed with their normal rotation for the next three games -- Hernandez and Young facing the Braves on Tuesday and Wednesday to open the nine-game homestand and Roenis Elias taking on the White Sox in Thursday's series opener.
But Iwakuma was jumped ahead of rookie James Paxton and will face the White Sox on Friday, followed by Paxton on Saturday. The Sunday starter against the White Sox is currently undetermined, with Hernandez, Young and Iwakuma then pitching the next three days against Toronto.
Sunday's decision boils down to either bringing Erasmo Ramirez or Taijuan Walker up from Triple-A Tacoma or going with a bullpen day, with long reliever Tom Wilhelmsen given another spot start. That option would presumably depend on how much the current eight-man bullpen gets used in the next five games.
Walker, the club's top prospect, gave up eight runs and eight hits in 2 1/3 innings in a rough start Monday in Albuquerque to put his Triple-A record at 4-3 with a 5.44 ERA in 10 games. McClendon said that was disappointing, but wouldn't be a determining factor.
"That has nothing to do with it," he said. "Obviously I'm disappointed in his numbers down there, but if he was the guy we're going to bring, that wouldn't have anything to do with it."
Ramirez won his last start Saturday in Albuquerque, allowing just two unearned runs on seven hits over 6 2/3 innings and is 3-4 with a 3.74 ERA in 11 Tacoma starts. He also threw seven innings of two-run ball with 10 strikeouts in a spot start for Seattle against the Mets on July 22.
"Erasmo is throwing fairly well," McClendon said. "And he threw well when he was here. He gave us an opportunity to win games. I would say he's definitely in the mix, so is Walker. The bullpen is an option, because we have eight guys. We're just not sure yet."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.