The plan is for Cashner to throw off a mound in Mesa, Ariz., at the Cubs' training facility, and then join the team in Pittsburgh on Monday. A Cubs' source said it will take more than a month for Cashner to be able to pitch competitively in the big leagues.
If Cashner gets through his rehab OK, the Cubs hope he can pitch in the major leagues in September.
Cashner was throwing a bullpen session in Cincinnati as part of his final rehab when he re-tweaked the rotator cuff. He originally suffered the injury during his first start of the season on April 5. He was placed on the DL April 8.
Cashner, a top pitching prospect in the Cubs' system, has appeared in 54 games (mostly out of the bullpen). He has a 2-6 career record and a 4.53 ERA.
Bruce Levine covers the Cubs for ESPNChicago.com.