Rams coach Sean McVay suggested Kupp's injury isn't serious, saying the rookie wideout merely suffered "a little tweak," Alden Gonzalez of ESPN.com reports.
Kupp has already been ruled out for Saturday's exhibition against the Chargers, with McVay pointing out that the rookie has already been plenty busy through the first two weeks of the preseason, having caught eight of 10 targets for 105 yards and a score. Kupp worked as the first-team slot receiver in both contests, making a strong case to have a key role in the Week 1 offense. It's unclear where Tavon Austin (hamstring) might fit in, as Sammy Watkins and Robert Woods are expected to start on the outside.