The Toronto Blue Jays made a move to fill a hole in their depleted rotation on Saturday.
The 35-year-old was acquired for cash considerations after Clay Buchholz went to the IL after dealing with a shoulder issue prior to his last scheduled start.
Jackson had a 3.33 ERA in 17 starts for Oakland last year.
Jackson was previously acquired by the Blue Jays on July 27, 2011, but then dealt on the same day to the St. Louis Cardinals as a part of the package for Colby Rasmus.
Once he plays a game, the Blue Jays will be the 14th Major League team Jackson has suited up for since debuting with the Dodgers in 2003.