The Bucs waived quarterback Sean Renfree to make room on the 90-man roster for Fitzpatrick.
Fitzpatrick is a 12-year NFL veteran. He has started 116 games, including 27 over the past years with the New York Jets.
He has 25,888 career passing yards, 166 touchdown passes and a 79.9 passing rating.
Before his two-year stint with the Jets, Fitzpatrick played for the St. Louis Rams (2005-06), Cincinnati Bengals (2008), Buffalo Bills (2009-12), Tennessee Titans (2013) and Houston Texans (2014).
The Rams drafted Fitzpatrick in the seventh round of the 2005 NFL Draft out of Harvard.
The Buccaneers needed to find a quality back-up quarterback for starter Jameis Winston after Mike Glennon signed with the Chicago Bears in free agency. The other quarterback currently on Tampa Bay's roster, Ryan Griffin, has never started a regular season NFL game.