Astros manager Joe Espada said Wednesday that De Los Santos has been shut down due to a right knee strain, Chandler Rome of The Athletic reports.
It's unclear when De Los Santos might be cleared to throw again. The right-hander posted a 4.36 ERA and 62:24 K:BB over 66 innings between Atlanta and Houston in 2025. If healthy, De Los Santos is pegged for a middle relief role in the Astros' bullpen.