Bloomquist played just 48 games last year for the D-backs after missing the first two months of the season with an oblique injury and then another two months in midseason after breaking two bones in his left hand after getting hit by a pitch, but he returned for the final month of the season and wound up hitting .317 in his limited action.
Bloomquist played for Seattle from 2002-08 after being drafted by the Mariners in the third round in 1999 out of Arizona State. He is a native of the Northwest, having grown up in Port Orchard, Wash.
Bloomquist has played every position except catcher during his 12 seasons in the Majors, including the past three years with the D-backs.
The Mariners return Brad Miller at shortstop and Nick Franklin at second base, and Bloomquist is capable of playing both those positions, as well as the outfield. Seattle has just three outfielders -- Dustin Ackley, Michael Saunders and Abraham Almonte -- under contract from last year's final roster.
Speaking on Saturday, before word of Bloomquist's signing came out, general manager Jack Zduriencik acknowledged that he wanted to add to the middle-infield mix with Miller, Franklin and Carlos Triunfel all extremely young.
"We've seen glimpses and flashes of these guys having talent," Zduriencik said. "But they've got to come back and be prepared, and they should be challenged in Spring Training. As you continue to look at other options, either through trade or free agency, you do what's best for your club in the long run. We like what we've seen, but we're not going to give anything to them."
Bloomquist had a .360 on-base percentage and .367 slugging percentage last season in 139 at-bats while playing 48 games, which was his least playing time since his rookie season in Seattle in 2002. He hit .302/.325/.398 in 324 at-bats in 80 games in '12.
For his career, Bloomquist is a .271 hitter with 17 home runs and 207 RBIs in 973 games.
He's played 329 games in the outfield, 282 at shortstop, 132 at third base, 123 at second base and 37 at first base in his career. Bloomquist became a free agent after his two-year, $3.8 million deal with the D-backs expired after this past season.