Yankees general manager Brian Cashman previously told MLB.com that Pettitte wouldn't participate.
The 40-year-old left-hander had shown interest in pitching for Team USA and former Yankees manager Joe Torre, but Torre said last week that the Yankees had expressed reservations due to Pettitte's injury history, including a broken ankle suffered in June. He was out until September, finishing with a 5-4 record and 2.87 ERA.
Pettitte also told the Yankees he would not participate in the WBC, MLB.com previously reported.
Torre had said last week that he would make the final decision regarding Pettitte's inclusion on the roster but indicated he would not pressure Pettitte or defy the Yankees.
"I'll probably discuss it with the Yankees a little more just to see," he said. "To me, the most important thing is to make everyone comfortable with what's going on. I certainly don't want to put any players in a stressful situation because that's not what we're doing here."
Information from ESPNNewYork.com's Wallace Matthews was used in this report.