Unless it says, "probably won't sign," he will sign. "Undecided," or "may sign if the deal is right," just mean he's probably going to ask for more than slot, and it seems to me the number is usually 150-200% of slot (although I just saw a guy ask for triple slot with a "may sign").
If it says "probably won't sign," but he's represented by an agent, he might or might not sign. If he's represented by his mother it's about 95% that he won't sign-- I've only seen one of them sign, and that for $11.7M.