© 2012 MLB Advanced Media, L.P. All rights reserved.

09/13/12 7:15 PM ET

Wilhelmsen throws a curve at opponents

TORONTO -- Most closers these days have an upper-90s mph fastball, but one thing that separates Seattle's Tom Wilhelmsen is his ability -- and willingness -- to drop a nasty curveball on batters in normal fastball counts.

The first-year closer struck out Toronto's Brett Lawrie looking at a 79-mph hook in Wednesday's 3-2 win, then followed by getting Colby Rasmus swinging at the same pitch before procuring his 26th save.

After a recent rough patch with his command, Wilhelmsen said his confidence in the curve has returned.

"I've been struggling with that curveball as of late," he said. "But I said something the other day about how I just need to keep throwing it out there and keep throwing it until [the struggles were] gone. So that's what I did."

Wilhelmsen had back-to-back one-run saves in the first two games of the Blue Jays series, giving him 19 saves in 20 opportunities since the All-Star break, the most in the AL in that span.

"He did a nice job working through a couple tough days," said manager Eric Wedge. "That's the true test of a closer. We've seen him steadily work his way back and he's been real good the last three outings or so. He seems much more relaxed, the ball is coming out of his hand the way you like to see it, he's confident in all his pitches. Those aren't easy save opportunities we're seeing him get and he's doing a great job for us."

As for the curveball? The same unpredictability it brings to opposing hitters makes Wedge uncomfortable at times, as well, but he's learning the benefit of that pitch in tough situations.

"It's huge for him," Wedge said. "The confidence he has in it is just as important. Sometimes it makes me a little nervous, but he's comfortable throwing it at any point, as he's proven time and time again. The confidence he has in that pitch is tremendous. And now he mixes in the changeup to left-handers, and that's been a good pitch for him, as well."

For Wilhelmsen, it's all pretty simple.

"I'm hitting the strike zone," he said. "That's all I can ask for right now."

Iwakuma excited to face fellow Japan native Darvish

TORONTO -- For Mariners rookie Hisashi Iwakuma, every start in the Major Leagues is something of a new experience. But on Friday in Texas, he'll undergo a more familiar first with the chance to face Japan countrymate Yu Darvish when Seattle takes on the Rangers.

Iwakuma, 31, pitched against Darvish six times in Pacific League games in Japan and the two were teammates on Japan's 2008 Olympic team and the 2009 World Baseball Classic championship squad.

This will be the first time they've competed against each other in the U.S., with Darvish holding a 3-2 edge in wins in head-to-head games in their homeland.

"We are friends, and sometimes we get dinner together and sometimes we talk on the phone," Iwakuma said through interpreter Daisuke Sekiba. "I'm looking forward to pitching against him. Of course, it's fun waiting to face each other at the Major League level. In Japan, we played against each other a couple games. So we expect that, it's just now we're here."

Darvish, 26, received far more attention after signing a six-year, $60 million deal with the Rangers and has put up a 14-9 record with a 4.14 ERA for the AL West-leading Rangers. But Iwakuma has quietly made a mark with the Mariners after agreeing to a one-year, $1.5 million deal.

Since moving into the rotation in midseason, he's gone 5-3 with a 2.80 ERA in 12 outings, including a 4-0 loss to the Rangers in his second start in July. That game was in Seattle and now he faces the potent Texas lineup in hitter-friendly Arlington.

For Iwakuma, that's a more significant challenge than facing his friend from Japan.

"It's different, because I'm going to pitch against the Rangers," he said. "That's the biggest difference."

Millwood's shoulder concerns could alter rotation

TORONTO -- Veteran right-hander Kevin Millwood said it was too early to tell how his right shoulder was reacting on Thursday, a day after he was removed after five innings and 66 pitches due to shoulder stiffness.

Millwood's situation leaves Mariners manager Eric Wedge waiting on how he's going to play out his rotation during next week's homestand. The pitching is set through Sunday with Hisashi Iwakuma, Jason Vargas and Blake Beavan starting this weekend in Texas.

But the Mariners haven't announced their plans for the Orioles series beginning Monday at Safeco Field, with young right-handers Erasmo Ramirez and Hector Noesi already in the mix for extra starts as September callups.

Wedge has said Ramirez will likely get a couple more starts in the final three weeks after picking up his first Major League win Tuesday and Noesi will get at least one shot. Their availability makes it easier to hold Millwood back if he's not ready.

"He's about the same today," Wedge said before Thursday's series finale with the Blue Jays. "We'll have to give him a couple days before we decide what we're doing. Of course we have coverage here now with Noesi and Ramirez, so we'll be OK. But we'll give him some time to see how he feels and just go from there."

Millwood felt tightness in his shoulder early in Wednesday's start, which he wound up winning with his five innings of two-hit, two-run ball in the 3-2 victory. The 37-year-old said it's something he's dealt with before, but knew he couldn't keep pushing as he struggled to maintain his velocity.

"I think everything has hurt at some point," he said. "But that game was too close to go out there and try to be a hero or try to pitch when I didn't feel I could do the things I need to do."

Worth noting

• When five Mariners pitchers combined to two-hit the Blue Jays on Wednesday, it was the eighth time this season Seattle has held an opponent to two or fewer hits (two no-hitters, one one-hitter and five two-hitters). The Orioles are the next-closest Major League team in that category with five games with two hits or less.

• The Mariners announced the extension of their contracts with four of their Minor League teams on Thursday. Double-A Jackson, Class A High Desert, Class A Clinton and Rookie League Pulaski had contracts expiring at the end of this year, but have now been extended through the 2014 season.

The Mariners had previously announced a two-year extension with Class A Everett, while a four-year deal with Triple-A Tacoma is in play through 2014.

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.