OTTB hard swelling fetlock

I had the farrier come out recently and he noticed that Merlin's front left fetlock is bigger than the other. He checked it for flexion and Merlin didnt seem bothered by it. I have touched it and he also does not flinch when I do,...The swelling seems "hard" and is only on his front left fetlock. He stands with it forward, not wanting to place his weight on it though...
Im very concerned about this. Its hard to determine whether him not wanting to put weight on it is from the fetlock or because he just has sore hooves from having his feet trimmed. Any ideas on what this might be?

Is he lame when he moves? My ottb developed fetlock swelling last year and I wrapped him and gave him stall rest. A few days later an absess blew out the back of his heel bulb. So, it could be pre-absess swelling. However, my ottbs swelling felt warm and fluid filled.

My mare has scar tissue around her fetlock that is hard but it doesn't bother her at all..

Go a week without riding him, if you gets really restless take him out for a walking on the lunge, if the swelling goes down you can ride him but look out for it in future. If it persists, I would call the vet, just to be sure.

Here are some pics...Definitely not fluid.
I flexed it and he didnt mind. He is not lame at the trot, it only seems to bother him when he is standing around?

Disregard this post; accidental.

Has he always been that way, or is it a recent thing? Looks like arthritis to me.

Looks like an osselet to me.
Very common in OTTBs

"Understand whether or not the osselets are changing, or “set”. If the ankle is stable, the horse is not lame, the joint space is intact and the animal’s condition hasn’t changed significantly in its recent history, then the vet may actually be able to give you a “thumbs up”, depending upon what job you have in mind for the horse." - CANTER website

Good luck :)

Here's a few good websites to describe it to ya.

http://www.bloodhorse.com/horse-raci...s/873/osselets
OTTB Health Series: Osselets « CANTER New England's Blog

The description of osselets sounds very similar to this! Thanks MoonIndigo.
He is sound at the moment. Doesnt bother him at all when touched or even flexed...Ill keep an eye on this :)

You're very welcome!!