The Cincinnati Reds' nightmare road trip just got worse. In the fourth inning of Thursday's series finale against the Chicago Cubs, rookie starting pitcher Rhett Lowder exited the game with what the team later called "shoulder discomfort."

Lowder had just walked the first two Cubs batters of the inning and thrown one pitch to Michael Busch when catcher Tyler Stephenson called for the trainer and manager. The severity of the injury isn't immediately clear, but Lowder appears headed to the injured list—a tough blow for a pitcher who was already coming off the worst start of his 14-game career, lasting just 1⅓ innings in Pittsburgh five days earlier.

The injury bug has been relentless for Cincinnati's rotation. The Reds already had three starting pitchers on the IL before Lowder's exit, including ace Hunter Greene (elbow surgery for bone chips), who is expected to miss more than half the season. No. 2 starter Nick Lodolo (blister) is due to return from the IL for Friday's series opener against Houston, while left-hander Brandon Williamson (shoulder fatigue) remains on the 60-day IL. Lowder himself missed all of last season recovering from a pair of injuries.

To make matters worse, reliever Connor Phillips struggled mightily after replacing Lowder, allowing the Cubs to explode for a seven-run inning. The Reds now return home licking their wounds, hoping Lodolo's return can provide a much-needed spark. For a team already dealing with its longest losing streak in two years, this latest setback is a tough pill to swallow.