Peyton Manning: PR Guru Slams Al Jazeera ... 'They're Backtracking And Retreating'

Al Jazeera is in full panic mode about the Peyton Manning story ... so says Manning's hired gun Ari Fleischer who tells TMZ Sports the news organization appears to be waving the white flag.

Ari tells TMZ Sports, "Their story was not credible to begin with and it’s not credible now," adding, "Al Jazeera is backtracking and retreating."

Fleischer is referring to a "Today" show appearance made by Al Jazeera reporter Deborah Davies Tuesday morning ... where Davies said that the network never asserted Peyton himself ever used HGH.

Peyton's camp believes Al Jazeera is contradicting their story and scrambling to save face.

Manning has been reluctant to say outright whether they'll file suit ... but you have to believe his camp smells blood in the water.