Nathan (elbow) will begin his rehab assignment with Double-A Tennessee, Gordon Wittenmyer of the Chicago Sun-Times reports.

EDGE Analysis

Nathan signed a major league deal with the Cubs in mid-May, as has been recovering from Tommy John surgery that forced him to miss all of last season. The 41-year-old could be a huge boost to the club's bullpen if he can work his way back from the injury, and could join Chicago around the All-Star break if he is effective and everything goes according to plan.