Gdula's Golf Simulations: Farmers Insurance Open

Rory McIlroy is a huge betting favorite this week, but is he actually a sensible bet? See what thousands of simulations have to think.

Volatility is the name of the game in golf, and picking winners isn't easy. With fields of 150-plus golfers sometimes being separated by how a putt or two falls each week, predicting golf can be absurdly tough.

We'll never be able to capture everything that goes into a golfer's expectations for a week, but we can try to account for that by simulating out the weekend and seeing what happens.

The Process

I'll keep it simple: I track weekly results from the PGA Tour, the European Tour, and the Korn Ferry Tour.

Using a combination of the OWGR's field strength numbers and datagolf's field strength numbers, I adjust each golfer's score relative to the field. The ultimate goal is to place a score from the Waste Management Open, the BMW International Open, and the Knoxville Open on level playing fields. This adjusted strokes metric lets me see how golfers are performing across all tours.

Their adjusted stroke data is combined with their round-to-round variance to see how the field is likely to perform when playing the event out thousands of times.

Here are the results for The American Express.

Win Odds

Golfer Wins FanDuel
Golfer Wins FanDuel
Rory McIlroy 16.1% +600 Jon Rahm 9.4% +800
Xander Schauffele 6.3% +1800 Hideki Matsuyama 4.8% +1800
Tiger Woods 4.7% +1000 Justin Rose 4.3% +1800
Gary Woodland 3.4% +2200 Rickie Fowler 3.0% +2700
Patrick Reed 2.7% +2700 Sungjae Im 1.9% +3100
Tony Finau 1.9% +2900 Jason Day 1.9% +2200
Jordan Spieth 1.8% +4500 Collin Morikawa 1.6% +3100
Byeong Hun An 1.6% +6000 Jason Kokrak 1.4% +6500
Scottie Scheffler 1.3% +3700 Cameron Smith 1.1% +3700
Marc Leishman 1.1% +4500 Brandt Snedeker 0.9% +4500
Billy Horschel 0.9% +5000 Joaquin Niemann 0.8% +4500
Sebastian Munoz 0.8% +10000 Phil Mickelson 0.8% +8000
Francesco Molinari 0.8% +5000 Keegan Bradley0.6% +9000
Jhonattan Vegas 0.7% +19000 Matthew Wolff 0.7% +6000
Rory Sabbatini 0.7% +10000 Russell Knox 0.6% +10000
Ryan Palmer 0.6% +7000 Max Homa0.6% +26000
Lanto Griffin 0.5% +7000 Carlos Ortiz 0.5% +15000
Dylan Frittelli 0.5% +10000 Sunghoon Kang 0.5% +21000

Rory McIlroy (+600 on FanDuel Sportsbook) is a heavy favorite despite a pretty loaded field at the top. McIlroy has the distance to dominate Torrey Pines and finished fifth here last year. McIlroy's expected win percentage is about as high as a golfer's gets in a full field like this. Despite the +600 number, McIlroy actually has positive expected value on his name on FanDuel Sportsbook.

Xander Schauffele (+1800) also has the distance advantage on his side this week and grades out with positive expected value. At +1800, he needs to be at least 5.3% likely to win, and he took home the victory in 6.3% of my simulations. It's not a huge discrepancy, but that's what we get with looking for outright winners.

Actual positive expected value is scarce elsewhere, but we have a lot of borderline break-even opportunities, namely with Hideki Matsuyama (+1800), Rickie Fowler (+2700), Byeong-Hun An (+6000), and Jason Kokrak (+6500).

Longshots who look like decent stabs include Sebastian Munoz (+10000), Rory Sabbatini (+10000), and Carlos Ortiz (+15000), but I'd rather look at top-10 or top-20 bets for them. It's a tough field overall, and Torrey Pines requires a great all-around game, so dark horses are not popping for outright winner bets.

A balanced betting card is looking like the best approach, based on the sims.