*** I have a vet appoitment just looking for suggestions

I have a gelding that is lame in the round pen in one direction, but in a straight line or out in the field he is sound and streches out great, no head bob or anything... any suggestions. 

I thought it was an abses but nothing has come out yet, I currently have his feet wrapped with magic cushion. 

Not uncommon at all. Putting them in a circle makes them use themselves differently than a straight line and puts pressure on things differently therefore making the soreness more obvious.

Just had one at the vet yesterday with a similar issue. Not lame at all, until she started into the turn going one direction. Trotting on asphalt she was sound going straight and to the left also, but once she started into her circle going right she would limp. Turned out to be a high suspensory injury, no swelling just the issue going right during the lameness exam. In my experience with abcesses, mine were constantly lame until the abcess blew out.

This sounds like it could be it, we think he was playing in the poop pile with the other gelding and pulled something. Thank you!! 

That is common for lameness. Could be any number of things. 

Just had the same issue 3 weeks ago.  Diagnosed with sore suspensory.  Reset shoes, gave some previcox and gentle riding in straight lines and he is all good now.

My mare is like that. Shes "off" in a circle on hard ground but sound on straight lines and in circles on soft ground. Ive spent alot of money getting it figured out. Xrays show some changes in her coffin bones and thin soles so she gets shod to help and I dont do alot of circles on her. She finished so all I do is keep her legged up and if I need to work on anything, its minimal. The vet said thats just her. We have checked everything in her legs. The shoes help her tremendously and when she gets about 5 weeks out she starts showing more signs of being sore. The farrier says its the way she breaks over. She wears aluminum PLR's and the farrier rounds the sides and toes more to help her break over easier. 

I keep her in cloud boots when we are hauling anywhere that isnt on grass or dirt. If she has to walk across concrete or rocks, she wears her boots. I will also pack her feet with Magic Cushion and leave her wrapped when I feel shes getting sore. 

Good luck with your gelding. It can be frustrating finding the cause.