In a corresponding roster move, the Blue Jays designated right-hander Sam Dyson for assignment.
Considering the contract, the Blue Jays expect DeRosa to be a right-handed hitter with defensive versatility available off their bench in 2013.
DeRosa appeared in 48 games with the Washington Nationals last season, hitting .188/.300/.247 over 85 at-bats while manning shortstop, first, second and third base and both corner outfield positions.
DeRosa has dealt with injuries throughout his career. The 37-year-old has been limited to 264 at-bats over the past three seasons due to his reduced role and injuries.
Over parts of 15 seasons at the major league level DeRosa has hit .270/.340/.412, though he's only managed a line of .220/.309/.269 from 2010-12.
Dyson appeared in two games for the Blue Jays last season. The 24-year-old allowed three runs on four hits with two walks and one strikeout in only two-thirds of an inning of work. He spent a majority of the year with Toronto's high- and Double-A clubs, maintaining an ERA of 3.04 over 39 appearances, including six starts.