I hate to hear that for ol' Tiger. I caught the "special announcement" 4 times on the golf channel last night. That's a good question Johnny. I wondered that myself.
I believe the reinjury came from his hoopla last year at the PGA when he made that putt I believe towards the end of the last round. He said he was ok but I've noticed a limp ever since. He looked ok when he was normally walking but any time there is any stress you could see he favored it and started to limp a little. It may be some clean up needed from his first causing a problem. According to the doctor he is supposed to be 100 percent after this surgery.
He should make a quick recovery because of his exceptional physical condition. Notice that he never mentioned the knee in discussing his second place finish at The Masters. That's class.
Yeah that is one thing about Tiger, we have seen him wince and limp some over the years but never hear him say a word about it. Then you have Wie and Phil hurt their wrists and it is all you hear about.
I think he would have had the surgery even if he had won the masters. There is plenty of time to recover before the US Open.
He probably had it planned all along, but only delayed it to have a chance at the Masters. He is only supposed to be out 6 weeks or so. Expect him to be back better than ever this summer.