SEATTLE -- Center fielder Franklin Gutierrez was placed on the seven-day disabled list with a concussion on Friday and the Mariners recalled right-handed reliever Steve Delabar from Triple-A Tacoma to take his place on the roster.

Gutierrez was hit in the right side of the face on a pickoff throw by Boston's Franklin Morales in the fourth inning of Thursday's 1-0 victory and spent the night in the hospital for precautionary reasons, manager Eric Wedge said.

"He's home now," Wedge said. "We'll continue to monitor him day to day and go from there. Obviously he got hit pretty clean with the baseball. So we'll see how he feels as the week goes on."

Gutierrez will need to pass the mandated MLB concussion test before he can be activated. He must spend a minimum of seven days on the DL. If he can't return after 14 days, he'll automatically be placed on the 15-day DL, retroactively.

Gutierrez has had a run of tough luck with his health. He played just 92 games last season due to a digestive disorder and then a torn oblique muscle. A 2010 American League Gold Glove Award winner, Gutierrez started this season on the disabled list again after tearing a pectoral muscle early in Spring Training and then dealing with a heel problem during his comeback.

Now he's on the concussion DL after taking Morales' pickoff attempt in his right ear while going back to the bag as the ball sailed past the glove of Red Sox first baseman Adrian Gonzalez.

"That was kind of a fluke thing," Wedge said, "but Gut's been on the south side of quite a few fluke things the past couple years, so I feel bad for him. He's been playing well, so hopefully this is just another bump in the road and we get him back sooner than later."

Gutierrez, 29, had played just 13 games since coming back and was hitting .267 with two home runs and nine RBIs in 45 at-bats.

Delabar, 28, joins the Mariners for his third time this season. He has appeared in 27 games with a 1-1 record and 4.78 ERA.

Iwakuma to make first start; Millwood pushed back

SEATTLE -- With Kevin Millwood dealing with some minor soreness in his right groin, the Mariners have decided to push back his next start and will go with long reliever Hisashi Iwakuma in his place Monday against the Orioles.

Iwakuma, 30, was a starter during an outstanding 10-year career in Japan, but he has pitched exclusively in the bullpen this season in his first year in the Majors.

The right-hander is 1-1 with a 4.75 ERA in 14 appearances. His ERA is 3.18 when he's pitched three-plus innings, which he's done five times.

Millwood felt some pain in his previously injured groin during his last start Wednesday against the A's and was removed after 2 2/3 innings. He did some light throwing again Friday and seems to be doing well, but the Mariners will be cautious after he injured the same area on June 8 after throwing six no-hit innings against the Dodgers.

Manager Eric Wedge said Millwood likely would be pushed back to next weekend's three-game series in Oakland.

"We didn't want to put him on the DL, because we didn't want him going that long without pitching," Wedge said. "He's been throwing pretty good and we didn't want him to lose that feel, with the All-Star break coming, too."

With Iwakuma removed from the bullpen equation for now, the Mariners recalled Steve Delabar from Triple-A Tacoma to bolster their relief crew.

Wells seeing plenty of action since promotion

SEATTLE -- It's amazing how quickly things can change depending on circumstances, which Mariners outfielder Casper Wells discovered since being recalled from Triple-A Tacoma on June 13.

Wells had been sent down to Tacoma because he wasn't getting much of a chance to play, but since his recall he's become an integral part of the outfield rotation while hitting .394 (13-for-33) in 11 games. With Franklin Gutierrez going on the seven-day disabled list with a concussion, he'll get even more of an opportunity.

Wells scored the winning run in Thursday's 1-0 victory over the Red Sox and also made two excellent catches in left field to help Felix Hernandez nail down his shutout. With Gutierrez going on the DL and Michael Saunders sidelined Friday by illness, Wells was in center field in Friday's rematch with the Red Sox.

"It's a great example of why you do send people down, to really go down there and get after it and come back and be better," manager Eric Wedge said. "That's what he did. I'd heard he spent a ton of time in the cage down there and was working to be better, and he's had an opportunity to come back up here and play a little more. And now we're going to continue to do that."

Wells played a lot of center field while coming up in the Tigers' system, so he's not worried about transitioning there now as needed.

"It just means you're running around a little more, but the ball stays truer," he said. "You have to make sure your routes are right so the ball doesn't take off on you, but I'll take some reps there in batting practice and I'll be fine."

Wells was still soaking up his part in Thursday's win after scoring the lone run after doubling with one out in the ninth and then coming home on John Jaso's base hit. He slid around the tag attempt by Boston's Jarrod Saltalamacchia and then slapped home plate as the ball rolled out of the catcher's glove.

"I saw where he was headed and the direction the ball was going, so I tried getting to the outside," Wells said. "As his glove made contact with my face, I saw the ball trickle away and I knew all I had to do was smack the plate and we'd won."

Is there a better feeling in baseball?

"Maybe hitting a walk-off home run to win the World Series," Wells said with a laugh, "but as far as a regular game is concerned, that doesn't get to happen too often. That was pretty cool."

Worth noting

• With Michael Saunders sidelined by illness and Franklin Gutierrez on the seven-day disabled list with a concussion, Chone Figgins got the start in left field on Friday night. And the fourth outfielder? That would be utility infielder Munenori Kawasaki.

"We can put him anywhere," manager Eric Wedge said. "He can run around and do what he has to do."

• When John Jaso hit his pinch-hit single to beat the Red Sox 1-0 on Thursday, he became the sixth player in Mariners history to break up a scoreless tie with a walk-off RBI and the 13th pinch-hitter with a walk-off hit. Jaso leads the Mariners with seven game-winning RBIs despite his limited at-bats in his first season with Seattle.

"I knew he put up good at-bats and was a good on-base guys and had good hands, but those late clutch situations, I wasn't aware of that," Wedge said. "That's just something I've seen this year."

• Former Mariners pitcher Mark Langston will throw out the ceremonial first pitch before Saturday night's game as part of the team's ongoing 35th anniversary celebration.