Guillen, 36, was a three-time All-Star while with the Tigers between 2004-11, but played just 28 games last year after sitting out the first three and a half months while recovering from microfracture knee surgery and then missing the end of the season with a wrist injury.
Guillen becomes the 26th non-roster invitee to the Mariners camp, which opens in two weeks in Peoria, Ariz. He figures to compete for time at third base and in the outfield, if healthy.
Of his 1,248 career games playing the field over 14 seasons, 856 have been at shortstop, but he hasn't played there since 2007. He's played 189 games at third base, 84 at second, 71 games at first and 48 in the outfield.
The Mariners' third-base situation remains up in the air, with youngsters Kyle Seager and Alex Liddi competing with Chone Figgins, who struggled last year and will be tried in a utility role this spring.
Guillen is a career .285 hitter with a .355 on-base and .443 slugging percentage, with 124 home runs and 660 RBIs. He hit .232 with three home runs and 13 RBIs last year in 95 at-bats.
Guillen originally came to Seattle in 1998 along with pitchers Freddy Garcia and John Halama as one of three young prospects acquired in the July 31 Trade Deadline deal with the Astros for Randy Johnson.
He was the starting shortstop on the Mariners team that won 116 games in 2001, then was traded to the Tigers in '04 for shortstop Ramon Santiago and Minor League infielder Juan Gonzalez. With Detroit, he was named to the All-Star team in 2004, '07 and '08 and racked up a .297 batting average and .842 OPS over eight seasons.