Jackson, 28, is still owed approximately $1.3 million of his $7.7 million salary this season.
The Cubs designated Mike Olt for assignment to make room for Jackson on the 40-man roster.
During Jackson’s six seasons, he’s played for two teams (Detroit Tigers and Mariners) hitting .273 with 54 home runs and 284 RBI. In 107 games with the Mariners this season, Jackson is hitting .272/.312/.387 with 46 runs-scored and 38 RBI.
Jackson will provide Cubs with a lot of outfield depth. When Jorge Soler returns from the disabled list, the Cubs will have seven outfielders including: Chris Coghlan, Dexter Fowler, Chris Denorfia, Kyle Schwarber, Matt Szczur and Soler.
While the Cubs have tried looking for a leadoff batter this season, Jackson will provide the Chicago with a true leadoff man. Jackson has 219 at-bats in the No. 1 batting spot this season and is hitting .265 with 23 RBI.
There’s no indication when Jackson will join the Cubs lineup.