League sources told the Detroit Free Press that Johnson inked a one-year deal with the Lions. Financial details of the contract weren't disclosed.
Johnson, who started three games for the Washington Redskins last season, completed 52-of-91 passes for 590 yards, three touchdowns and four interceptions. Before his stint with the Redskins, the 33-year-old quarterback bounced around between NFL teams and various football leagues.
The Tampa Bay Buccaneers selected Johnson in the fifth round of the 2008 NFL Draft out of the University of San Diego. The Lions mark the 13th NFL team for the veteran signal-caller, who also played for the United Football League's Sacramento Mountain Lions and was expected to suit up for the San Diego Fleet of the Alliance of American Football League before the Redskins signed him in 2018.
Johnson has appeared in 33 career NFL games, garnering eight starts. He has completed 148-of-268 throws for 1,632 yards, eight touchdowns and 14 interceptions.
Johnson's most significant playing time came with the Buccaneers, when he saw action in 26 games (five starts). He picked up his first NFL win as a starting quarterback last season with Washington.
The Lions searched for another quarterback following Savage's head injury in the first quarter of Thursday night's preseason loss to the New England Patriots. He was placed in the concussion protocol, according to the Detroit Free Press.
Savage has now been placed in the league's concussion protocol in 2016, 2017 and 2019.