The change, approved in November, was not disclosed until J.J. Henry said Thursday he would stick around The Gallery course in Tucson, Ariz., next week with hopes of getting into the field. Henry is No. 65 in the world ranking and would be the first alternate.
In previous years, the 64-man bracket was set at 5 p.m. Monday during the week of the tournament. If someone withdrew after that, his opponent advanced to the second round by a forfeit.
This year, if anyone withdraws after the bracket is announced Sunday night, the first alternate would take over that player's seed.
Much attention is on Arron Oberholser, who has not played in six weeks while recovering from a back injury. If he were to withdraw before Sunday, Henry would be the No. 64 seed and face Tiger Woods in the first round. But if Oberholser were to withdraw after the bracket is released Sunday night, Henry would be the No. 47 seed and face David Toms.
Oberholser has said he plans to play if his back feels good enough.
Those on the alternate list must be within the top 100 in the world to be eligible.