Evans was dismissed for a challenge on Bolton midfielder Stuart Holden and will now miss Premier League encounters with West Ham and Fulham.
He will now also miss the FA Cup semi-final against Manchester City at Wembley on April 16th.
"The referee has seen the player had a bad injury," observed Ferguson, who watched the contest from the directors' box as he began a five-match touchline ban.
"Both players went for the same ball, with their feet raised, and Jonny caught the lad.
"Once you raise your feet you are putting yourself in a dangerous area. It was unfortunate but we cannot complain."