At this point it's definitely a rumor. When he had the last surgery, as rolub said, there were some that worried because there have been cases where this surgery didn't work out well at all. That it was one of those surgeries that, if it didn't take right, or if it wasn't done well, could really end a career.
But everybody involved said it went well. So unless he's hit a wall or suffered some sort of setback, I tend to believe the doctors and Winslow who say he's going to be ready for camp.
However, there is that part of me that knows this is the way you cushion the blow if something like Winslow being done for the season is coming. And you'd want to do it this way, too, because of what happened with LeCharles already.
We'll see, I just get the sense this is a little like one of those Lis Franc things, where it's not a major injury, but if it's handled wrong, or if something goes wrong it turns into a huge, huge problem. I think that's why people are worried. But the guy's got time, and there's still a month before the draft. So even if, worst case scenario, he was really hurt, the team has some time to draw up plans to attack their offseason and draft accordingly and they shouldn't get caught flat-footed on this.