McIlroy has received steady support at the Westgate Las Vegas Superbook, and he is now listed ahead of Dustin Johnson as the betting favorite this week at Baltusrol Golf Club. The Ulsterman, whose odds opened at 8/1 after The Open and was available at 9/1 on Tuesday, is now available at 7/1.
According to Westgate manager Jeff Sherman, his book has received more money on McIlroy than all but one player in this week's field - Phil Mickelson, who won this event at Baltusrol in 2005 and is currently 15/1.
Here is a look at the odds on some of the tournament favorites as of Wednesday afternoon:
7/1: Rory McIlroy
8/1: Dustin Johnson
10/1: Jason Day
12/1: Jordan Spieth
15/1: Phil Mickelson, Henrik Stenson
20/1: Sergio Garcia