The West Brom boss has condemned the defender's actions after he was shown a straight red card by Mark Clattenberg for spitting at Tottenham's Kyle Walker
The Baggies were reduced to 10 men when Mark Clattenberg showed the Macedonian, who is currently on loan from Dynamo Kyiv, a straight red card for the incident.
Clarke's side went on to lose the game 1-0 thanks to a Gareth Bale strike, leaving the Scot to lament the actions of his defender.
Speaking after the game, Clarke said: "The game changed with the sending off.
"I'm absolutely disgusted with Goran's behaviour. One of the group has let the players down.
"He has let everyone down. It would be a strong case for him to receive disciplinary action"
Peter Odemwingie, who has seen his share of controversy in the past week, has defended Popov over social networking site Twitter, writing: "Just had Popov the Albion man on phone. He is not on twitter but asked me to pass a msg to Albion fans that he is sorry for the red card."
"Goran Popov: sorry for letting the team and the fans down. All players worked very hard and his mistake cost the team 3 points."
"What happened to Goran happens once in years. He was the player of the month last month. Thats life. Ups and downs."