"He's on a plane right now, and unless he changes his mind in the air there will be a press conference tomorrow and he will retire," the official said.
The 38-year-old is 240-138 with a 3.88 ERA in 16 seasons with the Yankees and Houston Astros. He made three All-Star teams and won 20 games twice.
Pettitte will rest his tender elbow and spend more time with his family, something he has said he wanted to do since he was a member of the Houston Astros. He was one of the most clutch pitchers in baseball, having won 19 postseason games, an all-time record.
His off-the-field ties to Roger Clemens and the steroid scandal will probably destroy his Hall of Fame chances; however, these next few years will tell us how players linked to steroids will receive votes into the HOF.