SEATTLE -- Center fielder Franklin Gutierrez suffered a mild concussion in the fourth inning of the Mariners' 1-0 victory over the Red Sox after getting hit on the right side of his face with a pickoff throw by Franklin Morales on Thursday night.
Gutierrez, who will be re-evaluated Friday, had just reached base on Seattle's first hit of the game leading off the inning when Morales' throw over sailed past the glove of first baseman Adrian Gonzalez and caught him flush in the face.
Gutierrez was down on the ground for about two minutes before being helped off the field by trainers. He was replaced by Michael Saunders.
Gutierrez, 29, has battled health issues for the past two seasons and was playing just his 13th game since coming off the disabled list on June 13. He partially tore a pectoral muscle early in Spring Training, then suffered plantar fasciitis in his heel while making his comeback.
The 2010 American League Gold Glove Award winner is hitting .267 with two home runs and nine RBIs since his return. He played just 92 games last year due to a long bout with digestive issues at the start of the season, then a month-long stint on the DL at year's end after tearing his oblique muscle.
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.