Aiyuk (hamstring) didn't take part in the portion of Wednesday's practice open to the media, Nick Wagoner of ESPN.com reports.
Aiyuk made just one appearance during exhibition season, gathering in one of three targets for three yards in preseason Week 2 against the Chargers. Since then, he picked up a minor hamstring injury that kept him out of the 49ers' preseason finale, as well as recent practices. There doesn't seem to be too much worry about his ability to be ready for Week 1 at Detroit, but his status nonetheless will be monitored over the next week and a half.