He couldn't use a wedge cos the ball wasn't fully in the rough.

The wedge would have been held up and hit the ball thin

The ball on the other hand, sitting on the short stuff would have had nothing to stop it flying, so, thinned by the wedge, it would have shot across the green.

unless he anticipated that and used a putting stroke ...

... or a putter.

It was his only choice and he got it up over the hill onto the green which was the most important thing.

The last putt was like a knife to the gut.