I read this entire thread and have to ask: do y'all play golf?
For those of you saying "It can't be the swing" or "with his talent, this can't happen" or the 3-4 who said he could/should "work it out in a few range sessions" or those who speculate that he didn't work hard enough this Winter (as if you have any idea, or know, or even know what is effective in terms of practice time for a world class pro), do you actually play golf?
He is a human being trying to make a golf ball move the way he wants in the air using a piece of iron. Thats hard. Everyone on this thread knows sometimes it goes and it doesn't come back for a while. Thats why Golf is fun. Thats why Golf isn't chess or darts or bowling. Sometimes it comes. Sometimes it goes. I got as low as a 6.5 then shot a 108 one day, and a 97 a few days after that. I got so frustrated trying to break under 5 that I quit for a month (or four) - recently started posting again (not that anyone would remember me lol). Then shot 88, 82, 82 after a few range sessions last week and I can't wait to play again.
It happens. It comes and goes. You can't diagnose it from the outside. The golf channel talking heads said it was his knees one day, then said it was his putter the very next day.
Walking off the course was a BS move. That said, he is 23 and I have some sympathy for him (I did some stupid stuff when I was that age and walking off a golf course wouldn't make the top 10). He's a good kid going through a rough patch. Will he come back? Probably. But who knows.
Its absolutely not an equipment thing, and I find it very hard to believe its because he didn't "work hard" enough.