Cubs manager Craig Counsell said Monday that Boyd (biceps) threw a bullpen session Sunday and is on track to rejoin the rotation early next week against the Phillies, Kyle Williams of the Chicago Sun-Times reports.
Boyd will make one rehab start later this week with Triple-A Iowa before being re-inserted into the Cubs' rotation. The veteran left-hander made two starts for the Cubs before getting hurt, allowing eight runs (seven earned) over 9.1 innings but with 17 strikeouts and three walks.