LOUISVILLE—Valhalla Golf Club is a wet golf course even when it's dry out.
The course itself sits within a flood basin. The humidity in Louisville routinely touches 100 percent, and it's been raining for most of the week.
"It never fully dries out," says PGA Tour putting coach Ralph Bauer. "When it rains, it gets really soft."
Pros generally love soft greens. It means they can throw darts where they're looking, and know the ball stick when it lands. The same is true when they fire drives into fairways, but that's not always a good thing. Soft fairways always bring with them the ever present threat of mudballs.
If the name itself doesn't give it aways, mudballs are when a glob of mud sticks to your golf ball.
The rules of golf stipulate that golfers are allowed to clean their golf balls before teeing off, or after marking it on the green. But when the ball is in the fairway, you play the ball as it lies. Mud and all.
The only exception is when tournament officials allow golfers to play lift, clean and place—which they're not this week (as our own Joel Beall reports).
Much as players in the field might like to...
"We're pro golfers, we're not professional mud readers," Xander Schauffele said after his second round.
As Xander implies there, mudballs are extremely difficult to judge. So how do pros play mudball golf? Here are the basics.
How to play mudball golf like the pros
The ball goes in the opposite direction of where the mud is. That's because the mud is heavy, and even though most of it flies off milliseconds after impact, that process alters the axis and spin of the ball as it launches.
"Mud left, ball right," Trevor Immelman explained simply. "Mud on top, ball goes lower."
The more backspin a shot has, the more severe the mudball's effect will be. It's why a common strategy you'll see is pros doing some combination of taking more club, trying to hit a lower knockdown shot, and swinging softer.
All those things take backspin off the ball, and lessen the mudball's effects. It's why you see Xander Schauffle hitting an 8-iron from 183 yards below: Because he's trying to bunt a draw into the front portion of the green (which he did successfully).
Ultimately, what makes mudballs so hard is that players don't know if they're going to move a lot more, or a lot less than they thought, so pros always try to aim in the way that gives them a buffer.
Once you do all that? All that's left is to pray to the Golf Gods.
"I was praying that the mud on my ball wasn't going to do something," Schauffele said of his thoughts before a bad mudball on Friday. "I feel like I made a nice pass at it ... I look up and my ball's just duck-hooking across the property. That pisses me off, for sure."