Everett's roster is limited to 35 players, and the Mariners needed temporary space there after acquiring left-handed pitchers Nick Wells and Jake Brentz from Toronto in the Mark Lowe trade on Friday and assigning them to the AquaSox.
Jackson was the sixth overall pick in the 2014 Draft out of Rancho Bernardo High School in Escondido, Calif., and he hit .280 in 23 games last year for Seattle's Rookie League team in Arizona.
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB, read his Mariners Musings blog, and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.