Andino, 28, is a career .235 hitter in parts of eight seasons with the Marlins and Orioles. He started 233 games for Baltimore over the past two seasons, mostly at second base and shortstop, and earned $1.3 million last year in his first season of arbitration eligibility.
"The addition of Robert Andino gives us some experienced infield depth with a player who has played multiple positions," said Mariners general manager Jack Zduriencik. "With Robert having Major League and playoff experience and still relatively young, we thought that it made sense to make this trade and let him come in and compete."
Unless he signs a long-term deal, Andino will have two seasons of arbitration eligibility with the Mariners before becoming a free agent in 2015.
Robinson, 25, hit .215 with five home runs and 26 RBIs in 90 games over the past two years for Seattle while earning the MLB minimum of $480,000 as a midseason addition in 2012.
The Mariners are looking for a versatile infielder to replace Munenori Kawasaki, who was released after batting .192 in 104 at-bats in his first season after coming over from Japan. Andino could also be capable of challenging incumbent starter Brendan Ryan at shortstop, if he can bounce back to his 2011 form when he played a career-high 139 games and hit .263 with five home runs and 36 RBIs.
Andino, a 6-foot, 195-pounder, saw that average fall to .211 with seven home runs and 28 RBIs in 127 games this past season, with 99 of those games coming at second base.
Andino is regarded as a quality defender who has played 211 games at second base, 123 at shortstop and 39 at third base in his career, along with five games in the outfield in four seasons each with the Marlins and Orioles.
The Miami native saw considerable action at second base the past two seasons for Baltimore in place of Brian Roberts, but the Orioles expect to have Roberts healthy in 2013 and also recently claimed Alexi Casilla off waivers from the Twins. The Orioles thus were debating whether to non-tender Andino rather than face a pay increase in arbitration.
Robinson, 25, was in a similar position with the Mariners, fighting the numbers game at a position where Seattle likely will add more competition in free agency or trades this offseason. Like fellow outfielders Mike Carp and Casper Wells, Robinson is out of Minor League options, so he would have had to either make the 25-man roster next spring or be exposed to waivers before being sent down.
Robinson thus had a hunch something might happen this offseason, though he still sounded a bit surprised shortly after the deal went down.
"I knew it'd be something a little different because I am out of options," he said. "The Mariners knew the type of player I am in their organization, but I guess this is a better fit for me going to the Orioles. Everything happens for a reason, I'm a true believer in that. I'd like to thank the Mariners for the opportunity to play in the Majors.
"I'll just have to start over and make new friends. But I'm not going to forget the guys I shared those first moments with in Anaheim in 2011 [when he made his Major league debut]."
After being recalled from Triple-A Tacoma on July 23, Robinson played 46 games for Seattle last season, including 39 starts in left field, while batting .221 with three home runs and 12 RBIs.
Robinson was acquired at the July 31 Trade Deadline in 2011 along with Chih-Hsien Chiang in a three-way swap that sent pitchers Erik Bedard and Josh Fields to the Red Sox. At the time, Robinson was a Dodgers prospect and he made his big league debut a few weeks later with the Mariners, hitting .210 with two home runs and 14 RBIs in 44 games as a rookie.
The 5-foot-10 switch-hitter from Los Angeles batted .265 with nine home runs and 41 RBIs in 83 games for Triple-A Tacoma last year before his recall by the Mariners.
Andino broke into the Majors as a 21-year-old with the Marlins in '05, but never played more than 44 games in a season at the big league level in his four years in Florida.
He was traded to the Orioles in '09 for pitcher Hayden Penn and filled a backup role until the past two seasons when Roberts ran into health issues. Though his offense slumped this past season, Andino was regarded as a tough competitor and important component on an Orioles team that proved to be one of baseball's biggest surprises by earning an AL Wild Card berth.
Andino hit .417 (5-for-12) in six playoff games for the Orioles, who lost to the Yankees in the American League Division Series.
Now, Robinson will see if he can find his niche with Baltimore.
"When we played against them, I felt they had a pretty good, energetic team," he said. "For me, it's a good fit. The way I play the game, I hustle, run into things and try to beat the opponent any way I can. The way they played against us, they didn't quit. I don't quit either. We'll see what happens. I have a good feeling it's going to be a good year again."