Furcal, who missed the 2013 season with Tommy John surgery, would play second base for the team. He hasn't played that position since May 5, 2004, for two innings as a member of the Braves.
The 36-year-old hit .264 with five home runs and 49 RBI in 121 games with the Cardinals in 2012. He was named an All-Star for the third time that season.
He is a career .281 hitter with 113 home runs and 585 RBI in 1,605 games (36 at second) in 13 seasons. Furcal spent six years with NL East divisional foe Atlanta.
In 2013, veteran Placido Polanco received a one-year deal from the Marlins to man third base after an injury-plagued 2012. He hit .260 with one homer and 23 RBI in 118 games.
Miami entered the offseason hoping to add experienced bats to a young lineup of players. The offense, which finished last in almost all statistical categories, needed help at the catcher and infield positions.
On Tuesday the Marlins agreed to a three-year, $21 million deal with catcher Jarrod Saltalamacchia. Both Saltalamacchia and Furcal are switch hitters.
"When you get thrust into the Major Leagues having only 60 at-bats above A-ball, it's a tough league out there," Marlins general manager Dan Jennings exclusively told FOX Sports Florida last week. "It's unforgiving, and we had guys fight through some tough times. And really, they did a great job. They energized our entire fan base and their teammates, and that's big.
"But we need to find some guys we can put around them to help them develop and to take a little pressure off them and let them realize, 'Listen, you've got less than a full year in the Major Leagues.' Get them in their correct role in the lineup and then the clock can speed up."
Solano, who has played 12 games at third over the past two seasons, hit .249 with three home runs and 34 RBI in 102 games in his second season with the Marlins. Dietrich, whom the Marlins acquired last offseason in a trade with the Rays, hit .214 with nine home runs in 57 games last season.
The Marlins are likely to continue to pursue adding bats to their lineup.