Mickelson’s miss at the par-5 15th underscores the importance of being committed to your line, especially on putts inside six feet. Lefty was admittedly indecisive on his read and made a “tentative” stroke; as a result, he left the putterface open and missed the hole entirely. He wasn’t alone – Chad Campbell and Kenny Perry left some big putts short down the stretch as well.
The tendency under pressure is to slow the putterhead down coming into the ball, which rotates the face open. Here are two ways to correct this: 1) Focus on the forward half of your stroke, accelerating the putterhead toward the hole. A good way to practice this is by practicing the Hole-y Roller Drill. Place a ball in front of your putter and, without making a backstroke, push the ball toward the hole. This will encourage the putterhead to release toward the hole and square up at impact. 2) Commit to your line or whatever it is you’re aiming at. If you see the putt as an “inside right edge” putt, then hit it to that spot. If it turns out your read is wrong, then so be it, but find out if it’s right or wrong. So long as you’re committed to your original read, you’ll make a better stroke and hit the ball more solidly.