Routledge was given his marching orders for his reaction to a poor challenge from Rangers midfielder Karl Kenry four minutes from time against his former club.
Swansea manager Garry Monk said after the 1-1 draw that he hopes "sense prevails" and the FA overturns the decision, which left Routledge facing a three-match ban.
And the governing body revealed on Friday that the 29-year-old former Tottenham man will no longer serve a suspension.
A statement on the FA website said: "Following an Independent Regulatory Commission hearing on Friday 2 January 2015, Swansea City's Wayne Routledge has had his claim for wrongful dismissal upheld.
"Routledge was dismissed during his side's 1-1 draw against Queens Park Rangers on New Year's Day for violent conduct.
"The three-match suspension has therefore been withdrawn with immediate effect."
Routledge will be in contention to face League Two side Tranmere Rovers in the third round of the FA Cup on Saturday.
