The poll from InsiderAdvantage found that incumbent Democratic Senator Raphael Warnock leads the former University of Georgia running back by three points. The survey was conducted on 4 October with 550 likely voters and had a margin of error of 4.2 per cent.
Last month, the same poll showed that Mr Walker led Mr Warnock 47 to 44. Those numbers are now reversed.
The poll came after The Daily Beast published a story that Mr Walker, who has said he opposes abortion in all cases, paid for a girlfriend’s abortion in 2009. Mr Walker has vehemently denied the report even though The Daily Beast published images of a get-well card he sent to his girlfriend along with a check for $700.
But Mr Walker’s son Christian has vehemently criticised his father.
Matt Towery, the founder of InsiderAdvantage, said that the firm was already polling the race before the allegations.
“We scrapped that poll and surveyed last evening after newspapers, television news, and social media bombarded voters with the various stories,” he said in a statement.
Mr Towery said that in that poll, Mr Warnock led by one point.
“The good news for Warnock is that following these newest events, he leads by three points,” Mr Towery said. “The good news for Walker is that the difference between the two polls is well within the survey’s margin of error.”
The numbers come ahead of Mr Walker and Mr Warnock’s debate next week and before early voting begins in the state on 17 October. If neither candidate wins a majority of the vote, the race will go into a runoff.
“I continue to believe that the polling suggests that this race is headed to a General Election runoff,” Mr Towery said. “Warnock was at 47% in our September survey of this contest and despite the latest controversy around Walker, remains at the same percentage.”