INDIANAPOLIS (AP) -Former Pro Bowl defensive tackle Corey Simon will miss the rest of the season after being placed on the non-football illness-injury list Thursday by the Indianapolis Colts.

The Colts, citing federal privacy laws and a decision to protect Simon's privacy, did not divulge the illness.

Simon, the biggest defensive lineman on the team's roster at 300 pounds, was expected to be a major part of the Colts' run defense this year, but he has not played or practiced since banging his knee in early August.

Several weeks later, he had arthroscopic surgery, but a written statement issued by team president Bill Polian said the injury and illness weren't connected.

``It is not football related,'' Polian said. ``Fortunately, we are told it is not life-threatening, but it has severely limited Corey's ability to condition, practice or play and has been debilitating for him.''

Simon's agent, Roosevelt Barnes, said he thought it was only the knee injury that kept him out.

``Corey had surgery on the knee and had been rehabbing, getting ready to play,'' Barnes said in a telephone interview from his office in Roanoke, Ind. ``That's my understanding as to what kept him off the field.''

There is no prognosis when Simon might return to playing football. Polian's statement said Simon had been checked at the Mayo Clinic.

``We reached this decision reluctantly and only after extensive tests were run by our medical staff and many outside medical specialists,'' Polian said. ``Corey has shown some improvement in recent days, but none of the medical personnel we consulted believe he can safely return to football in the near future.''

Simon was not available in the locker room before practice, and the team did not issue its statement until after practice ended and coach Tony Dungy had already spoken with reporters.

Barnes said Simon was disappointed. ``Eventually he expected to play,'' Barnes said. ``Corey loves to play, as you know.''

For several weeks, Simon's condition has been a mystery. Dungy and Polian had said Simon continued to have tests done, but never mentioned the illness.

Simon signed with the Colts last year after sitting out training camp in a contract dispute with the Philadelphia Eagles. The Eagles released Simon on Aug. 28, and four days later the Colts signed him to a multiyear contract - hoping he would be the final piece to their Super Bowl puzzle.

Instead, Simon struggled with his weight and had to learn a new defense. He finished with 31 tackles, no sacks and forced one fumble last season, and did not play at his previous Pro Bowl level.

The Colts expected more from Simon this season. When he reported to training camp, Simon said he had lost 20 to 25 pounds and expected to have a better season. On Aug. 4, he banged his knee in camp and did not return.

The Colts (4-0) rank near the bottom of the league in run defense, giving up 155 yards a game.

Polian said he hoped Simon could play next year.

``Corey can now devote himself to a complete and unhurried recovery,'' Polian said. ``Our fervent hope is he will be ready to return to the field next season.''

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