Saunders, 32, signed a one-year, $6.5 million deal that included a potential second year at $8.3 million with Seattle just prior to Spring Training. Instead, the Mariners initiated a $900,000 buyout to void that second season after the left-hander went 11-16 with a 5.26 ERA in 32 starts.
The two players will be free to negotiate new deals with any of the 30 Major League teams, including Seattle, beginning on Tuesday. The Mariners had five other players -- Raul Ibanez, Kendrys Morales, Humberto Quintero, Oliver Perez and Endy Chavez -- become free agents on Thursday.
Teams have until 9 p.m. PT on Monday to exclusively negotiate with their own free agents, after which they're able to sign with any team.
The Mariners' 40-man roster is now at 34 players, with reliever Stephen Pryor moved from the 60-day disabled list to the 40-man roster on Friday.
Gutierrez won an American League Gold Glove Award in 2009, when he hit .283 with 18 home runs and 70 RBIs in 152 games in his second season after being acquired from the Indians. But after signing his four-year deal with the Mariners in 2010, Gutierrez ran into a lengthy series of health issues that resulted in him playing just 173 of the team's 486 games over the last three seasons.
Gutierrez played 92 games in 2011 after two disabled list stints with a stomach ailment and a strained oblique muscle. He appeared in just 40 games in 2012 after opening the year on the DL with a torn pectoral muscle, then missing two months with a concussion in midseason after getting hit in the head on a pickoff throw to first base.
Gutierrez played just 41 games again this past season after a series of hamstring issues. He rejoined the team in late August after a lengthy stint in Triple-A Tacoma and said he'd been diagnosed with an inflammatory condition called ankylosing spondylitis, which he believes contributed to his host of ailments over the previous two years as well.
Gutierrez said medication was helping him control that condition, and he hit .235 with five home runs and 13 RBIs in 23 games after returning for the final five weeks. For the season, he hit .248 with 10 home runs and 24 RBIs in 145 at-bats.
Gutierrez had a slash line of .255/.305/.383 with 45 home runs and 194 RBIs in 478 games over five seasons in Seattle and was regarded as one of the premier defensive center fielders in the game when healthy, though manager Eric Wedge moved him to right field upon his return this past season in order to reduce the strain on his body.
Saunders had a shorter history with Seattle, working as the No. 3 starter behind Felix Hernandez and Hisashi Iwakuma this year after signing as a free agent. He ranked 10th among left-handed starters in the American League with 183 innings, but he gave up the second-most hits in the Majors with 232 and opposing hitters batted .311 against him with a 1.60 WHIP.
Saunders is 89-81 with a 4.30 ERA over a nine-year MLB career that has included stints with the Angels, D-backs, Orioles and Mariners.