Contract details are out, via MLBTR's Tim Dierkes:
Mesoraco gets a four-year, $28MM deal from Reds. No options. Can reach $30MM with escalators.— timdierkes (@timdierkes) January 26, 2015
The deal buys out his remaining years of arbitration, as well as one free agency year. It's a nice reward for Mesoraco, who broke out as an All-Star last year, and could end up being a coup for the Reds if he's able to repeat his performance.
More as we get it.