There is a HUGE difference than him having a nice time turned out and then the stress of a show and running barrels..
My thought exactly, I know lame horses that can run in a pasture lol. I don't know the situation but from what is sounds like I don't think your horse is ready to run barrels. If he hasnt seen the pattern and has been off for sometime, and is recovering from and accident, why rush him for one race? Especially if you already have a horse to use. If you want to get some show experience under his belt just bring him along and tie him to the trailer and maybe ride him a LITTLE (as in walking around, that is if he is able to do it)