Patriots' offensive lineman Nick Kaczur has not been a training camp participant since last Friday morning, and he may not return to the practice field any time soon.
ESPNBoston.com's Mike Reiss is reporting tonight that Kaczur has told teammates that he has a "significant" back injury that will sideline him indefinitely, and possibly the entire season.
Kaczur had been working at left guard since the spring, rather than his usual right tackle spot, due to the Patriots' prolonged contract standoff with Pro Bowler Logan Mankins. He left the field early during New England's third training camp session a week ago and has not been seen since.
With Kaczur on the shelf, Dan Connolly and Ryan Wendell have been working at left guard; on Thursday, newly-signed Eric Ghiaciuc took some snaps there as well. Rich Ohrnberger, who was a day-of-game inactive 13 times last season, and rookie Ted Larsen could also contribute at guard.
A Patriots team spokesman declined to comment.