Collier reverted to the Raiders' practice squad Monday, per the NFL's transaction log.
Collier was elevated to the Raiders' active roster Saturday for the first time this season. However, he was a healthy scratch for Sunday's game against the Raiders despite Raheem Mostert (ankle/knee) being inactive. Collier has not appeared in a regular-season game this year, and his last opportunity to do so is Week 18 against the Chiefs.