MLB Network and The Detroit News reported Thursday night the longtime Cardinals reliever is finalizing a deal with the Tigers. Rosenthal, 29, was released by the Nationals on Sunday after posting a 22.74 ERA in 12 games.
Rosenthal saved 121 games in St. Louis from 2012 to 2017. He was named to the 2015 All-Star Game and recorded a career-high 48 saves that year.
Rosenthal is 11-25 with a 3.37 ERA in 340 career games. He has 440 strikeouts in 331 1/3 innings since debuting in 2012.
Rosenthal had Tommy John surgery in August 2017 and missed all of last season. He signed a one-year deal with Washington in November 2018.
Rosenthal didn't record an out in his first four appearances with the Nationals. He walked 15 hitters in 6 1/3 innings.
Detroit is 26-50 this season. The Tigers have not made the playoffs since 2014.