Houck (elbow) threw off a mound Tuesday, Alex Speier of The Boston Globe reports.

EDGE Analysis

Houck has been dealing with a sore flexor muscle since early May, and Tuesday's throwing session marked the first time that he had thrown off a mound since he suffered the injury. The right-hander only threw fastballs during his bullpen session, but it was encouraging to see him make some progress in his recovery.