According to Nick Piecoro of AZCentral Sports, the sides have agreed to a two-year, $4 million contract.
The D-Backs' signing of Mathis comes on the heels of their non-tender of catcher Welington Castillo, who may have gotten too expensive in arbitration for what they are apparently looking for.
Last season, with the Miami Marlins, Mathis hit .238/.267/.333 with two homers and 15 RBI over 132 turns at the plate. Due to good defense, he was worth 0.1 WAR, according to FanGraphs.
Statistics aside, Mathis has been said to have a positive impact on the clubhouse.