The centre-back was given his marching orders for a challenge on Romain Vincelot in the 18th minute at Brisbane Road.
It forced the Saddlers to play for over 70 minutes with 10 men but they still managed to earn an impressive point and end the O's 100 per cent start to the League One season.
Saddlers boss Dean Smith admitted after the game he felt the challenge was not even worthy of a free-kick, labelling it "a great tackle".
Butler's straight red means he faces a three-match suspension unless Walsall are successful with their appeal, with a verdict due later this week.
- Sports & Recreation