Samuel is scheduled to undergo an MRI after exiting Sunday's 32-29 win over the Seahawks due to a hamstring injury, Ian Rapoport of NFL Network reports.
Samuel sustained the injury with 5:06 remaining in the third quarter, when he was tripped up by a Seattle defender and landed awkwardly while fumbling the football as he fell to the ground. The upcoming MRI will shed more light on the severity of the hamstring issue, but Rapoport notes that the fact that the 49ers ruled Samuel out of Sunday's game immediately is a foreboding sign. If Samuel ends up sitting out Week 6 against the Commanders next Monday, the 49ers would be left with Mike Evans, Brandin Cooks, Jacob Cowing and Jordan Watkins as their healthy options at receiver.