The deal is said to be two years and worth a total of $6.2 million.
The Sox currently employ Jarrod Saltalamacchia and Ryan Lavarnway at catcher.
The deal will become official once the 35-year-old Ross passes a physical.
Ross comes from the Atlanta Braves. He’s a career .238 hitter. He batted .256 last year in 62 games with 9 HR last year in Atlanta.
He also played a brief stint with the Red Sox in 2008.