Greenlaw did not play for most of the second half of Thursday's 12-6 loss to the Rams due to Achilles and knee tightness, Cam Inman of The San Jose Mercury News reports.
Greenlaw was making his season debut after recovering from a torn Achilles, so the nature of the injury is a concern. However, the team reported that he did not suffer another tear, instead saying that he was suffering primarily from fatigue and tightness in both his Achilles and knee.