"I am what I am," said Mike Webster. Then he corrected himself.

"Or rather, I was what I was."Seventeen years after an undersized, middle-round draft choice reported to the Pittsburgh Steelers, people now must get used to speaking of the great career of Mike Webster in the past tense.

The perennial Pro Bowl center and a mainstay on Pittsburgh's four Super Bowl champions, retired Monday, one week before his 39th birthday.

"It's been 17 wonderful years, but one thing you learn in this game is reality," said Webster, who spent the past two years with the Kansas City Chiefs. "It's time."