[Kitanna]

I see other have hit on the fact Saruman wouldn't have needed or known to bother with the three hunters at this point, so I'll forget what I was going to say which has been stated better by others.

However, maybe the old man was a vision of Gandalf sent by someone else. Who? I can't say. But it reads as a sort of foreshadowing that Gandalf is about to return and there is this hatted old man who may have been a vision to the hunters of what was to come. The problem with this theory is who would have had the power to show the three hunters that Gandalf was abroad in the land.