Everybody else will have a guage on his real value too, which might be a reason to let him go now while people think he's a top 5 SS. If you can get somebody good for him now, by all means do it. But if not, and people in your league are weary about trading for him, keep him. It'd be nice to keep him until Nomar gets back, but if you can get more for him in a trade now, it might be wise to do that, and upgrade another part of your lineup.
"Jack, will you call me, if you're able?"
"I've got your phone number written, in the back of my Bible."