What is wrong with the front driver's side wheel on my car? Here is a description.?

I have a 1997 Mercury Tracer. The car pulls hard to the left, and the front of the car shakes all the time, no matter what speed I am going. It even does it in reverse. I can tell it is coming from the front driver's side wheel, and it has gotten progressively worse over the past 2 -3 weeks. It almost feels like the tire is wobbling, but when I have someone else drive it, and I watch it, I can't see any noticeable wobbling going on. I am taking the car to a mechanic tomorrow, but I thought that I would throw the question up on YA to see if anyone knew what the problem might be. My best guess is a broken tie rod, does anyone else have any ideas? I will know the answer tomorrow. The correct answer gets 10 points.