Since the return of Michael Morse from the disabled list last week, Seattle has five healthy outfielders in Morse, Michael Saunders, Raul Ibanez, Dustin Ackley and Endy Chavez.
Bay, 34, hit .204 with 11 home runs and 20 RBIs in 68 games for the Mariners after signing a one-year, $1 million deal during the offseason.
Gutierrez has played just 18 games for the Mariners this season, batting .267 with five home runs and 11 RBIs in 60 at-bats. He's had two stints on the disabled list due to a strained right hamstring and hit .219 with three home runs and 22 RBIs in 37 games for Tacoma while on rehab duty.
Position players can spend up to 20 days on each Minor League rehab stint, so Gutierrez has returned to the Mariners. He could be sent out on another rehab stint in five days if needed.
"He's still not really 100 percent," said acting manager Robby Thompson. "He still has a couple good days and a couple bad days. We pulled him off and I think it's a five-day period where he'll continue to get treatment. He'll hit in the cage and throw and continue doing that, and he'll get back and start [another] rehab assignment then.
"Just talking to him, when he does come back we need him to be at a point where we can use him against right-handers and left-handers, maybe in back-to-back days," Thompson said. "If he's not playing, he needs to be ready on the bench to pinch-hit or pinch-run and go out to the outfield. As of right now, he's not really to that point where he feels comfortable or confident to come back right now."
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.