Boone, who turns 34 next March, hit .251 with seven home runs and 45 RBI in 104 games at third base last season for Cleveland. His deal with the Marlins could wind up being worth as much as $1.275 million, based on performance bonuses.
Boone, who will likely be the backup for Miguel Cabrera at third base for the Marlins, has also played second base and shortstop in his major league career.
He was an NL All-Star in 2003 for Cincinnati, then was sent to the New York Yankees later that season and wound up swinging his way into postseason lore. Boone became the fifth player in playoff history to hit a series-ending home run; his 11th-inning solo homer in Game 7 of the AL Championship Series allowed the Yankees to beat the Boston Red Sox and move on to the World Series, where they lost to the Marlins.
Boone injured his left knee playing basketball that offseason, needed two surgeries and eventually missed all of 2004, then was with the Indians for the past two years.
In 969 games with the Reds, Yankees and Indians, Boone has hit .264 with 115 home runs and 499 RBI.