Gutierrez, 29, had played only 13 games this season after coming back from a partially torn pectoral muscle when he got hit in the head by a pickoff throw to first base on June 28. After dealing with recurring headaches, he finally was able to make a rehab stint with Tacoma and hit .333 with seven RBIs and two home runs in seven games.
He'll provide some center field options for Wedge, with Michael Saunders having missed three games now with a groin injury after colliding with right fielder Eric Thames in the ninth inning of Friday's 9-8 loss to the White Sox.
Gutierrez just wants to finish this season up strongly after the difficulties of the past five months.
"For me, it's very important to be healthy," he said. "Everybody knows what's been happening to me the last couple of years. I just want to keep that behind me. The team is doing good right now. They're playing good baseball. I just want to be part of it. I'm going to come in and try to help my team any way that I can, and that's the most important thing for me right now."
Gutierrez was a 2010 Gold Glove Award winner and is one of the premier defensive center fielders in the game when healthy, but has struggled to stay on the field the past two seasons. He played just 92 games while hitting .224 in 2011 after dealing with a digestive issue early in the year and then straining his oblique muscle in the final month.
A career .256 hitter in eight years in the Majors, Gutierrez was batting .267 with two home runs and nine RBIs in 45 at-bats this season when he was hit in the face by Boston's Franklin Morales while going back to first base.
Wedge had him hitting second in Monday's game, back in the same spot he'd elevated himself to when he got hurt a second time.
"There's no sense wasting any time with it," said Wedge. "He's a veteran guy. We had him up there before when we had him, albeit it briefly, and he did a nice job for us. I like him up there. Time is running short in regard to this season, so there's no sense wasting any time. He's a good player and he's ready to go."
Gutierrez said it was the second concussion of his career, the first coming about 10 years ago as a Minor Leaguer when he got hit in the head with a 98-mph fastball and missed about a month's playing time.
Wells, 27, has hit .226 with eight home runs and 29 RBIs in 74 games with the Mariners. He snapped an 0-for-16 slump with a two-run home run in the fifth inning of Sunday's 4-3 loss to the White Sox.
Wells had lost playing time recently with Trayvon Robinson getting most of the duty in left field and Eric Thames in right. He'll be with the Rainiers for their season-ending eight-game road trip starting in Las Vegas on Monday night, then be eligible to rejoin the Mariners after Tacoma's season ends on Sept. 3.
"He gets a chance to go down there for a week and get everyday at-bats," Wedge said. "Trayvon and Eric have both been playing pretty well. Casper's playing time had obviously diminished, so he was the odd man out. We'll get him back up here in September."