Statistic: Greens in Regulation- 65.56% (96th on the Tour)
Hitting greens is hard. Players have to factor in wind, slope of both the lie they're hitting off and the green they're hitting onto, distance, club selection, and then they have to actually execute the shot. That was once Tiger's forte.
When a player doesn't hit greens, it becomes that much harder to make birdies, simple as that. Tiger's approach shots have been so erratic that he has not been putting himself in position to make birdie putts.
For example, at the British Open it seemed like Tiger was either putting for birdie from 40-60 feet away or putting for par from 4-6 feet away. That is not how you win championships, and he knows that better than anyone.
Before the British Open, I wrote about how I firmly believed Tiger had the upper-hand in the event. This was because he discussed in an interview how he had regained his comfort executing an array of golf shots. Well, we know how that worked out: tie for 23rd.
Hitting golf shots close to the pin isn't just about perfect mechanics, just like throwing a strike or shooting a free throw isn't just about mechanics. Instead, it requires confidence in both one's technique and in one's ability to hit the shot.
Prior to hitting his approach shot, Tiger might be able to visualize the shot he needs to hit because he's done it before, but he doesn't actually seem confident that he's going to pull it off.
It's most noticeable in his held off finishes and shorter and faster back-swings. But most of all, because he knows just milliseconds after striking the ball that it's not what he wanted to do, it results in his notorious profanity and visible anger.