A journeyman quarterback is a term used for an American football (typically NFL) quarterback who plays for several teams over a career. Such a player is typically signed to year-by-year contracts, and may be signed by a team to fill in for an injured starter. The term journeyman is normally pejorative.
The paradigm of a journeyman quarterback might be J. T. O'Sullivan, who spent time with 11 NFL teams (plus the Saskatchewan Roughriders and the Frankfurt Galaxy) during his career. Josh Johnson, who is still playing, has also spent time with 11 different NFL teams and the Sacramento Mountain Lions of the United Football League. Chris Chandler started for seven different NFL franchises during his career. He also started for the Los Angeles Rams and St. Louis Rams ten years apart. Ryan Fitzpatrick, who is still playing, has also started for seven different NFL franchises.
There is no accepted definition or threshold at which a person is regarded as a journeyman quarterback, and the term is descriptive rather than definitive. Dave Krieg enjoyed a stable 11-year career with the Seattle Seahawks, before leaving through Plan B free agency, and then played for five different teams (usually as a starter) over the remaining seven years of his career. But because the years of transition occurred during the later part of his career, Krieg is not generally perceived as a classic journeyman quarterback. Similarly, Mark Rypien, who played for seven years with the Washington Redskins (including a Super Bowl MVP performance in Super Bowl XXVI) before playing for seven different teams for a single season each over the remainder of his career, is not normally regarded as a journeyman for that reason.