Darvish (triceps) experienced pain during Thursday's bullpen session and will be reevaluated once the team returns to Chicago next week, Gordon Wittenmyer of the Chicago Sun-Times reports.
Darvish had no issues since throwing five innings during a rehab start Monday and was potentially going to start Saturday, but the re-emergence of pain Thursday complicates his return timeline. Mike Montgomery should remain in the Cubs' starting rotation for the near future with Darvish suffering the setback.