After rupturing his left ankle ligament last weekend, Rory McIlroy was forced to pull out of next week's British Open at St. Andrews. McIlroy is the reigning Open champion and will be the first to not make an attempt to defend the claret jug since Ben Hogan in 1954. 

At the time of McIlroy's injury announcement on Monday, he was the heavy betting favorite, receiving 36 percent of all money wagered on Open Championship futures at William Hill US sportsbooks. With McIlroy out, the bets that had been wagered on him are being spread around the board pretty evenly. 

According to William Hill US, the unique wagers placed (number of tickets, not amount of money) on British Open futures since Wednesday morning's announcement have been all over the place. Jordan Spieth has received 13 percent of wagers, which is just slightly more than Justin Rose and Louis Oosthuizen each at 12 percent.

Here are the 10 players that have had the most wagers since Wednesday at William Hill US sportsbooks:

Jordan Spieth 13 percent (9-2)
Justin Rose 12 percent (15-1)
Louis Oosthuizen 12 percent (18-1)
Dustin Johnson 10 percent (10-1)
Tiger Woods 9 percent (25-1)
Jason Day 9 percent (25-1)
Henrik Stenson 9 percent (20-1)
Rickie Fowler 8 percent (25-1)
Phil Mickelson 8 percent (25-1)
Adam Scott 6 percent (18-1)

As for which players are getting the most money put on them, the field (which is everyone not listed among the 80 players with individual odds) has received 17 percent of the money wagered since Wednesday. That likely means there are a few very large wagers put on the field (13-1) to win. Spieth has had 10 percent of all money wagered on him since Wednesday, followed by Dustin Johnson at 8 percent. Despite getting 12 percent of the tickets each, the amount being put on Rose (6 percent) and Oosthuizen (5 percent) is relatively low. 

Here are the 10 players getting the biggest percentage of all the money being wagered on the Open at William Hill US sportsbooks:

Field 17 percent (13-1)
Jordan Spieth 10 percent (9-2)
Dustin Johnson 8 percent (10-1)
Justin Rose 6 percent (15-1)
Tiger Woods 6 percent (25-1)
Louis Oosthuizen 5 percent (18-1)
Jason Day 5 percent (25-1)
Rickie Fowler 4 percent (25-1)
Henrick Stenson 3 percent (20-1)
Matt Kuchar 3 percent (60-1)
Adam Scott 3 percent (18-1)

There were no guarantees that McIlroy would have been at or near the top of the leaderboard at the Open, but that was the expectation. Now that he won't be participating, it's clear that his absence has made this year's Open much more difficult for people to predict. 

Jordan Spieth has two majors this year and is getting the most bets for the Open. (USATSI)

Jordan Spieth has two majors this year and is getting the most bets for the British Open. (USATSI)