thanks for he info! He has been on stall rest for the past week with light hand walking. It gets stiffer with more movement.

the only progress we have seen is that the heat is gone and swelling has gone down.
I went to ride him 2 sundays ago and he was leaning to the right and not wanting to push into the trot. I got off and noticed he was throwing is left back leg in and only putting light weight on it. Before we rode, his groundwork was fine and he was running around freely without me in the arena. So I figured he must have done something to it when he was goofing off. The next day the barn turned him outside in the outdoor mud arena, which probably made it worse!! So, for 2 days I put linamint (sp?) on it, on the 3rd day I ran cold water on it and called the vet. He said that obviously without seeing it, it's hard to say, but if I start to see noticeable healing and no more heat that light turnout indoors is good to make sure he doesn't stock up. He said no more linamint, but to run cold water on it daily.
So result is, no more limping, no favoring it, no heat, very little swelling, still noticeably stiff that does not work out.
I do plan on calling the vet again at the 2 week mark. I've just never had to deal with this before. We're not doing really heavy training, just trot work and circles a couple times a week, so I don't know how he might have done this. I always properly warm up and cool down as well.
He is going to be 4 april 1st.