The Yankees dared Derek Jeter to test the open market last week. And after the way they've talked about him in public, the free-agent shortstop would probably love to do nothing more.

But Mr. Jeter faces a significant challenge in doing so, and it has little to do with his age, his bat or his defense. In trying to elicit contract offers from other clubs, his most difficult task is convincing them he would actually leave the Yankees.

Though...