The midfielder was given his marching orders during the first half of Town's 2-1 home defeat to Doncaster for a challenge on Iain Hume, with the score goalless at the time.
Manager Graham Turner immediately expressed his anger at the decision post match and vowed to appeal the red card and consequent suspension.
And that appeal has been successful, with McAllister free to face Walsall at the Banks's Stadium this weekend.
Turner told the club's official website: "You just feel a little bit bitter towards the referee (Oliver Langford) as the decision may well have cost us a point, perhaps even three.
"It was an absolutely shocking decision, but fortunately justice has prevailed."