Ertz was seen working out on the side during the portion of Wednesday's practice that was open to the media, Tim McManus of ESPN.com reports.
The Eagles haven't previously revealed that Ertz is tending to an injury, but the team's first practice report of Week 13 will provide an explanation for why the tight end wasn't participating with the main group. Given that Ertz has logged 36 targets over the last three contests, it's possible that the Eagles are simply giving the 29-year-old some much-needed rest.