The Cubs also received cash in the deal, and designated infielder Mike Olt for assignment to make room on the roster. Jackson will be eligible to play in the postseason because the deal was done before September 1st. Any players traded from September 1st-on will not be able to play in the postseason.
The Cubs currently hold a five and a half game lead on the San Francisco Giants for the second NL Wild Card spot. Manager Joe Maddon spoke highly of Jackson's talents, as they add even more depth into a very young and talented outfield.
Maddon called Jackson a "complete player", highlighting his defensive ability and his ability to steal bases. The 28-year-old was set to leadoff and play centerfield for Seattle in Houston on Monday night, but was scratched from the lineup an hour before first pitch.
He was traded to the Mariners from the Detroit Tigers at the 2014 trade deadline, a three-team deal that included David Price. He is hitting .272 with eight home runs and 38 RBIs in 107 games this season.
The Cubs have dealt with injuries to Jorge Soler and Dexter Fowler, recently placing Soler on the disabled list with a strained left oblique. Jackson provides more youth to the roster, and more speed in the outfield to help the playoff-contending Cubbies make a run in October.