Hannahan hit .244 with four home runs and 29 RBIs in 105 games for the Indians last season. Hannahan is a career .234 hitter with 28 home runs and 159 RBIs in 505 games with the Detroit Tigers, Oakland Athletics, Seattle Mariners and Indians.
Hannahan appeared in 215 games for the Indians over the last two seasons.
Blaine Blontz of MLB Daily Dish reported that the Minnesota Twins, Chicago White Sox, Miami Marlins and the New York Yankees were interested in the 33-year-old left-handed hitter before he signed with the Reds.
Hannahan will serve as a backup to Todd Frazier, according to Rosenthal. Frazier batted .273 with 19 home runs and 67 RBIs in 128 games for the Reds last season. Frazier is hitting .264 with 25 home runs in 169 games with Cincinnati over the last two seasons.