In case you're not in the habit of checking the AJC Beat Blog (you should be, because Craig goes to every practice whereas I'm only able to get away from the office once a week or so), Jon Sim is undergoing surgery this afternoon for a fractured orbital bone. There's no knowing how long he'll be out until after the surgery and I'm not going to speculate about it. If you want to know what that's going to do to tomorrow's lineup stop by the Beat Blog.