The Cowboys placed Alexander (undisclosed) on the practice squad injured list Thursday.
Alexander was placed on Miami's injured reserve with a groin injury during the preseason before being cut from this list with an injury settlement Sept. 2. The seventh-year cornerback then went unsigned before landing with Dallas' practice squad Dec. 6, and he was elevated once for the Week 16 win over Philadelphia. Alexander will now have to sit out the remainder of the Cowboys' postseason run due to an undisclosed issue.