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05/03/2013 7:15 PM ET

Iwakuma, Saunders trade spots in starting rotation

TORONTO -- The Mariners tweaked their rotation for the club's three-game set against the Blue Jays following ace Felix Hernandez's start vs. Toronto on Friday.

Hisashi Iwakuma and Joe Saunders are still starting this weekend, but Seattle flip-flopped their turns in the rotation.

Iwakuma was originally supposed to be pushed back two extra days and go Sunday due to a blister he has been dealing with on one of the fingers of his pitching hand, but he will now get the ball Saturday.

"We had it set up one way, but we didn't feel the need to push Iwakuma back, because his finger is coming along nicely," manager Eric Wedge said.

Iwakuma has been dominant early on, sporting a 1.67 ERA, and a 0.69 WHIP -- the top mark in baseball -- while holding opponents to a .160 batting average over six starts. The 32-year-old has struck out 37 batters and walked just five, good for a 7.40 strikeout-to-walk-ratio, which ranks fourth among qualified Major League starters.

Saunders is coming off a complete-game victory against Baltimore in which he lowered his ERA by a full run to 5.25. Last September, the last time Saunders pitched in Toronto, he took a perfect game into the sixth inning as a member of the Orioles.

Brown takes over for Datz as third-base coach

TORONTO -- Triple-A Tacoma manager Daren Brown will serve as the Mariners' interim third-base coach while Jeff Datz, who was diagnosed with cancer on Saturday, is away from the team.

Brown went over signs in a batter's meeting prior to Friday's game and said he feels comfortable stepping in after being around the club during Spring Training. The only thing he's expecting to be different between coaching in the Minors and Majors is the speed of the game.

"I feel like I have a job to do," said Brown, who has been the manager at Tacoma in the Pacific Coast League for the last seven seasons. "Datz is our third-base coach here. He's not able to be here, he's doing what he needs to do to get well. I just feel like, for me, it's just step in and do the job until he gets things taken care of."

Brown, who will wear No. 52, filled in as the interim manager for the Mariners for 40 games in 2010 after the club fired Don Wakamatsu. Eric Wedge then replaced Brown the following season.

Wedge is happy to have him around.

"Brown has been managing and coaching third base for a long time," Wedge said. "He's familiar with everything we are doing. ... We'll just see how it plays out with Jeff.

"I'm very comfortable with him. He spent the entire time in Spring Training with us. He's very familiar with me and how we do things."

The Mariners wanted to make a permanent coaching move during Datz's absence after having Minor League catching coordinator John Stearns fill in this week on an emergency basis. Stearns will now take over for Brown as Tacoma's manager.

Chris Toman is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.