The midfielder apologised for the tackle.
"I apologise to the fans for getting sent off but no way was I pulling out of that tackle in a game of that importance. I'm sorry," he wrote on Twitter.
Ferguson was bemused by the 20-year-old's reaction.
"He blamed me! But he is young and he will realise the stupidity of it," said the Scot.
"Jonny Evans went for the ball but Shelvey was nowhere near and could have given Jonny Evans a really bad injury - he was very lucky actually."