The 40-year-old Blanco appeared in 37 games for the D-backs last season, hitting .250 with eight home runs and 12 RBIs in 112 plate appearances.
Serving as the backup to Miguel Montero (137 games), Blanco was the only other player on the roster to appear at the catching position last season.
The D-backs picked up their side of Blanco's $1.15 million mutual option earlier in the week, but he declined his end, opting for free agency. But he wasn't a free agent for long.
According to SI.com, Blanco will make $1.2 million next season.
Blanco, regarded as a strong clubhouse presence, hit four of his eight home runs over a 13-day stretch in May, including two against the Padres on May 16.
Defensively, he threw out 38.1 percent of attempted basestealers (8-for-21).
The D-backs are the ninth team Blanco has played for since beginning his Major League career in 1997 with the Dodgers.
He has a career .228 batting average and a .994 fielding percentage. Blanco has also thrown out 40.8 percent of attempted basestealers (237-of-581) in his career.
The D-backs' 40-man roster is currently at 33 players.