Late last year, he told a Houston television station his only considerations for 2009 were to return to the Yankees or retirement.
"The Yankees committed an awful lot of money to me and put it in my hands, gave me a player option and trusted me with that option," Pettitte, 36, told KRIV-TV in November. "It probably wouldn't be real honorable for me not to do anything other than shut it down or go back and play for (them)."
The veteran left-hander signed a one-year deal with the Yankees Monday that guarantees him $5 million.
Last season was Pettitte's first major league campaign without a winning record. He was 14-14 with a 4.54 ERA.