Detroit will be Johnson's 13th team since being drafted in the fifth round of the 2008 draft. Johnson started three games with the Redskins in 2018, throwing for 590 yards and three touchdowns.
The San Diego product was dspent the first three years of his career with the Buccaneers. He started five games from 2009-11, going 0-5 with five touchdowns and 10 interceptions.
Johnson has been a journeyman since leaving Tampa Bay. He played one snap in Cleveland in 2012 and was active for two games with the Giants in 2016.
Washington marked the most game action for Johnson since his stint with Tampa Bay. He completed 57.1% of pass attempts with the Redskins, adding 120 rushing yards and one touchdown.