This has been a problem for some time now. It's not really news except in the context of next week's all-star game. Otherwise, it probably wouldn't even be mentioned. He's been given periodic days off this year to rest it, so the all-star break gives him the chance to rest it a bit more. It obviously hasn't affected his production. Nothing to worry about IMHO. I have him and won't trade him.
"Trying to hit him was like trying to drink coffee with a fork." - Willie Stargell on Sandy Koufax