Samuel (knee) was spotted on the field for the open portion of Thursday's practice, Nick Wagoner of ESPN.com reports.
Samuel hasn't logged any recorded practice activity since spraining his left knee and ankle in a Dec. 11 win over Tampa Bay, but he looks poised to go down as either a limited or full participant on the 49ers' second Week 17 injury report, which will be released later Thursday. Samuel looks like he'll have a chance to put an end to a two-game absence and suit up this Sunday in Las Vegas, but his availability for that contest will be contingent on how he fares in practice Thursday and Friday.