Lewington's red card for an adjudged elbow on Saturday saw him follow team-mates Stephen Gleeson, Antony Kay and Alan Smith in earning three-match suspensions this season.
He told the club's official website: "I've gone to get the ball when I just should have just got back into my position, but I have grabbed the ball and their man has come to grab it and he's grabbed my arm and my natural reaction was to push him back.
"It wasn't an elbow, my arm was open, it's not bent, it's nowhere near his face and there is no force in it at all. The linesman has said I have elbowed him directly in the face with force.
"It is one of those things that, looking back at it, I shouldn't have even got involved in it, I should have just got back into my position."