Walton has been less than impressive in his time at Home Park and his actions at Oakwell has pushed Paul Sturrock over the edge.
The Plymouth boss has now taken further action and said: "Simon and I have had a discussion and I made it very clear how disappointed I was about the whole scenario. He has let all the players down.
"After careful consideration I have decided to put him on the transfer list and fined him two weeks' wages.
"The rest of it is internal as far as I am concerned."
After going to down to 10 men Barnsley took advantage and won the game two goals to nil.