Watkins broke his foot in Saturday's preseason opener and is expected to miss 6-8 weeks, NIck Wagoner of ESPN.com reports.
The injury is believed to have happened early in the game against the Chiefs but was only discovered after the game ended. Given all the players ahead of him on the depth chart, this injury will likely end Watkins' long-shot bid at securing a spot on the 49ers' 53-man roster.