Masterson (knee) was a limited participant in Wednesday's practice, Paul Gutierrez of ESPN.com reports.
Masterson appears to have sustained a knee injury in the Raiders' Week 4 win over the Browns, despite playing 54 total snaps (33 defensive snaps and 21 on special teams) and recording six total tackles. His participation Thursday and Friday will provide a better indication of his potential availability in Week 5, as the Raiders take on the Broncos.