While the Pirates are the front-runner in trade talks for A.J. Burnett, the Yankees have discussed the right-hander with four other teams, according to baseball sources. One of the clubs was among teams Burnett can veto per his contract, a source said, and the right-hander was unwilling to give in on that team. The identity of the other interested teams remains unknown. Burnett is owed $33 million over the final two years of his contract.