Lamb (concussion) was estimated as a non-participant on Tuesday's practice report, Michael Gehlken of The Dallas Morning News reports.
According to Rob Phillips of the Cowboys' official site, Dallas held what head coach Mike McCarthy described as a light "run-through" session Tuesday, but Lamb evidently hasn't advanced far enough in the NFL's five-step concussion protocol to take part even in non-contact drills. With the Cowboys' Thanksgiving Day game against the Raiders being just two days away, Lamb seems to be trending toward inactive status for the contest, though McCarthy noted the second-year wideout is staying mentally prepared to play. A more definitive word on Lamb's chances of playing against Las Vegas should arrive Wednesday, when Dallas releases its final Week 12 injury report.