The Veterans – Mark DeRosa, Rajai Davis, and Merkin Valdez
Though he only played for the Blue Jays for one season, Mark DeRosa is one of the most entertaining players to have donned the Blue Jay. Having slashed a decent .235/.326/.407 in 2013 as a 38-year-old, DeRosa spent the 2010 and 2011 seasons with the Giants, appearing in a total of 73 games for San Francisco.
Rajai Davis, another veteran who at one point was a Toronto Blue Jay, discreetly suited up for the Giants in 2007 and 2008, when he appeared in 63 games and stole 21 bases in 160 at-bats. Having spent three years with the Blue Jays, Davis, who recently signed a minor-league deal with the New York Mets, also played for the Pirates, Tigers, Red Sox, Indians, and Athletics. He is seventh in Blue Jays franchise history with 125 stolen bases as a member of the organization.
Another forgotten Blue Jay, Dominican pitcher Merkin Valdez, was traded from the Giants to the Blue Jays in January 2010 for cash considerations and proceeded to spend the next season in the Blue Jays organization, mostly for the Triple-A Las Vegas 51s.
In parts of three seasons with San Francisco, Valdez, now retired, pitched to an ERA of 5.24 in 67.0 innings. He also briefly appeared as a member of the Texas Rangers in 2011, suiting up for five games in September of that season.