Samuel (undisclosed) wore a blue no-contact jersey during Tuesday's unofficial practice, Nick Wagoner of ESPN.com reports.
Samuel has dealt with the occasional injury this season, missing one game (Week 7) along the way, so the 49ers may merely be exercising caution with the rookie wide receiver on the doorstep of the playoffs. Wednesday's practice report will provide the first glimpse into his on-field activity for the regular-season finale.