Arguably the Panthers' most notable veteran acquisition in the offseason, Hartwig injured his groin in the season-opening loss to the Atlanta Falcons on Sept. 10. His only playing time since then was a brief, mop-up appearance against Dallas two weeks ago. Last week, Hartwig re-injured the groin while doing a set of "power clean" lifts in the weight room.
"It's become a recurring problem," said Hartwig, who doesn't know when -- or even if -- he can return in 2006.
Doctors have recommended rest for now, and Carolina officials probably will wait a couple more weeks before revisiting the situation, but there is a chance Hartwig will be placed on injured reserve. If the rehabilitation continues to progress slowly, the five-year veteran may simply decide to shut things down for the year and proceed with the surgery.
The only positive for the Panthers is that second-year lineman Geoff Hangartner, who appeared in only six games as a rookie in 2005, has played very well replacing Hartwig as the starter the past seven games.
Hartwig, who termed this season "heartbreaking," would prefer to try to get back on the field, then have surgery after the season, but the schedule is running out on him.
"Obviously, I hope to rest it and rehab it," Hartwig said. "At the same time, I don't have a lot of time left if I'm going to contribute this season. "I hope to get back on the field in a couple of weeks. That's my goal ... but we'll see."
The former University of Kansas star, who started all but one game for the Tennessee Titans in the past three seasons, was signed by the Panthers to a five-year, $17 million contract this spring as an unrestricted free agent. Carolina was seeking to replace Jeff Mitchell, who had been a fixture at center, with a younger player, and Hartwig was seen by many in the NFL as one of the league's best young snappers.
Originally a sixth-round pick by the Titans in the 2002 draft, Hartwig is a self-made blocker, a player chosen by Tennessee to provide depth, but a guy whose work ethic and time in the weight room catapulted him into the starting lineup in only his second season. That work ethic, toughness and in-line blocking skills all made him attractive to Carolina coaches and personnel officials.
But in June, Hartwig underwent what was expected to be routine hernia surgery, with the procedure sidelining him for the first two weeks of training camp. Hartwig, 27, now feels the hernia surgery contributed to his groin injury in the season opener.
No matter when he has the groin surgery, in coming weeks or at the end of the season, the recovery period is expected to be 8-10 weeks. The priority, Hartwig said, is for him to be completely recovered when the Panthers begin their spring conditioning program. There is, he allowed, an incentive in repaying the Panthers for their investment in him.
"I did sign a big contract here," Hartwig said. "I know the team had high expectations for me, and I have extremely high expectations for myself. And it's really frustrating when you can't meet those expectations."
Len Pasquarelli is a senior NFL writer for ESPN.com.