Steelers head coach Mike Tomlin clarified that Porter suffered a knee injury in Saturday's 34-17 loss to the Ravens, Mike DeFabo of The Athletic reports.
Porter's injury was initially deemed a calf issue, but it was determined the knee injury was causing deferred pain to the calf area. Porter was originally injured in the first half, tried to return in the third quarter, but was eventually ruled out for the remainder of the contest. The Steelers face the Chiefs on Wednesday, making it a short week for Porter to try and get healthy.