I agree. While this would suck tremendously, this year is different than last year. If we can keep the rest of the team healthy, that hole can be covered up, especially with Salty hitting.
His defense will be severely missed, but think about it this way - Since April 15th, Pedroia has been hitting .221 with a .638 OPS. So if he goes down for a month, it's not like it was last year when he was on an absolute tear and the line up took a major hit. He's struggling to get going right now and has lost significant power. It's hard enough for him to hit with a screw in his ankle, if his knee is jacked up too, it's near impossible.
If getting Pedroia the surgery will get him back to being a .300/.375/.450 hitter from July - October, then I'm 100% for it. Scutaro or Lowrie can fill the gap at 2B and, honestly, could even be an offensive boost considering Pedroia's production this year. When Pedey is healthy, he puts a charge into this team. Lets get him healthy for the dog days.