ARLINGTON, Texas -- Jay Ratliff hinted that he has issues with the Dallas Cowboys' strength and conditioning staff on Wednesday, one day after the defensive tackle was placed on the reserve/physically unable to perform list with hamstring and groin injuries.

Ratliff underwent surgery for a sports hernia in December, ending an injury-plagued 2012 season that saw him play in just six games. Ratliff didn't attend every rehab session at Valley Ranch, ultimately preventing him from starting the season on time.

Ratliff will remain on the PUP list and miss the first six weeks of the regular season. Cowboys owner/general manager Jerry Jones called Ratliff missing the start of the season "a setback."

Sources told ESPNDallas.com that there was tension between Ratliff and the strength and conditioning staff, which is widely considered among the best in the NFL.

Ratliff has been frustrated by the rehab process and said that was one of the reasons he stayed away.

Jay Ratliff was placed on the reserve/physically unable to perform list Tuesday, meaning he'll miss the first six games of the season. AP Photo/Gus Ruelas

In comparison, defensive end DeMarcus Ware, coming off shoulder surgery, attended his rehab sessions and was ready to practice at the start of training camp.

Linebacker Alex Albright, who also had a sports hernia surgery following Ratliff's operation, attended the sessions and started training camp practices on time. Albright's back injury, which will require season-ending surgery, is unrelated.

Following the Cowboys' annual luncheon at AT&T Stadium to kick off the season Wednesday, Ratliff was asked why he didn't attend the rehab sessions.

"That's a good question," he said before refusing to answer it.

"I do, but rather not say. Let's just keep the focus on these guys going out there playing and winning games. I'm not going to be here and be a distraction to everybody. Just stay professional about the whole situation, but everyone involved knows what's going on."

Jones said Ratliff was in charge of his rehab away from Valley Ranch and "that's a combination of schedule and a combination of preference. A lot of that weighs into that."

Stephen Jones, the Cowboys' executive vice president, said Ratliff's hamstring is just tweaked but agreed with the player that his groin is still an issue.

"We're obviously hoping he gets back," Stephen Jones said. "We're ready to get him back and we're going to accommodate him in any way we can. We support Jay and obviously we think he can really help us this year."

Jim Maurer, the team's head athletic trainer, has been with the Cowboys for 24 seasons. In 2002, his staff was recognized as the NFL's athletic training staff of the year in a vote by peers.