Blanco will undergo surgery, performed by hand specialist Dr. Don Sheridan, on Wednesday in Phoenix.
Manager Kirk Gibson said that the team will have a better idea of when Blanco could return after the extent of the damage is determined during surgery. Indications are that he could miss the rest of the regular season.
"I don't know what the exact timetable is, but it will put him toward the end of it, for sure," Gibson said.
The D-backs claimed veteran catcher Wil Nieves off waivers on Monday to take Blanco's place.