"In a way, I sympathise with Antony because he obviously has talent, and I can see he does try sometimes. He looks angry and frustrated when he plays and because of this, he tries to do stuff and overcomplicates things, loses the ball and then becomes even angrier," the Bulgarian, who was at United from 2008-12, told Betfair.
"Antony needs someone on the pitch to show him where to run, how to run and when to release the ball. If he can't find the answers on his own, he needs a coach, a friend, an agent, his dad, to give him advice. He should even start to watch videos on clips of some right wingers who have been there and done it. After that, if he can't perform then it's clearly not going to work out.
"For me, watching as a fan, I get angry when I watch him because it's frustrating. I don't want to compare him to anyone because every player has difficult spells. If Antony can't get out of his, then he needs to go. If a season is too short to judge someone then Antony deserves a little more time because it's not fair. If he corrects his errors, then he will be good for the team.
"He needs to be mentally clever first and foremost and you need to know how to take criticism. If Antony's performances aren't up to the standards by the end of the season, I imagine he will look for somewhere else to go. The coaches at Man United need to give Antony advice. Then it will be up to him to understand it. That's it."