The 31-year-old left-handed hitting catcher comes with a $7.5 million option, which the Tigers could try to turn into an extension. He is slated to become an unrestricted free agent after next season.
Barnhart played eight seasons in Cincinnati, where he hit for .248/.328/.378 with a .696 OPS. While Cincinnati is commonly known as a hitter friendly ballpark, Barnhart hit just 51 home runs during his Reds tenure.
But the Tigers didn't trade their former second-round pick in 2019 for Barnhart's hitting or slugging, but rather for his defense, where he was awarded a gold glove in 2017 and 2020. Overall, behind the plate he threw out 32% of would-be base stealers, including a league-best 44% in 2017.
Barnhart will join Eric Hasse as the Tigers' top two catchers heading into next, and the team will likely rotate the two throughout the year.