Blanco, 39, was a backup catcher for the Mets in 2010 and hit .215 with a pair of homers and eight RBIs in 144 plate appearances.
Blanco has carved out a niche for himself over his 13 seasons in the big leagues as a backup catcher who is known for his outstanding defense behind the plate and leadership in the clubhouse.
The D-backs were in the market for a catcher to back up Miguel Montero. While they had capable young candidates for the job in John Hester and Konrad Schmidt, the club preferred to have someone with more experience.
The contract is believed to be worth around $1 million and may wind up including a mutual option for 2012.
Provided they get Blanco signed, the D-backs will next turn their attention to finding a right-handed bat who can play left field.
Two of the candidates to fill that role are free agents Austin Kearns and Xavier Nady.
Kearns, 30, played for the Indians and Yankees in 2010 and hit a combined .263 with 10 homers and 49 RBIs in 461 plate appearances.
Nady, 32, hit .256 with six homers and 33 RBIs in 347 plate appearances. He is particularly of interest to the D-backs because of his ability to provide insurance at first base in addition to the outfield.