The Dolphins' most troublesome unit has taken another hit.
Trainers shut down Dallas Thomas, the projected starting left guard, on Wednesday because of a left shoulder injury he suffered during Tuesday's practice. The team was already practicing without starting left tackle Branden Albert, who is still recovering from knee surgery.
Thomas, who was competing with rookie Jamil Douglas for the starting spot, has battled shoulder issues for most of his college and NFL career.
The Dolphins selected the former University of Tennessee standout in the third round of the 2013 draft despite knowing he had his right shoulder surgically repaired that spring.