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.