Dumoulin enjoyed a stellar 2017 season, claiming two time trial gold medals at the Road World Championships and winning the Giro d'Italia.
Priedler was his Sunweb team-mate for four years including during the 2017 Giro but was handed a four-year suspension back in June after being implicated in the Operation Aderlass blood doping ring. However, while admitting that he had extracted blood, the Austrian denied reinfusing the blood.
"I had my blood taken out but never put it back. But the thought and the fraudulent intent are already a crime," Priedler said at the time.
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However, the Austrian National Anti-Doping Organisation (OADR) gave the 29-year-old a four-year ban to run from Preidler's provisional suspension date of March 5, 2019 to March 4, 2023, with his results between 1 February 2018 and 5 March 2019 expunged.
Despite the denials, the Austrian public prosecutor has levelled a charge of fraud against the former Sunweb rider in relation to blood doping and the use of growth hormone inlcuding during the Giro two years ago up until this year, reports Salzburger Nachrichten. Should he be found guilty he could face up to five years in prison.
Dumoulin posted on social media that while he would not let the revelation taint his first Grand Tour triumph, he now realised that Priedler had undergone a personality change that should have set off alarm bells.
"I’m beyond proud of that victory and I always will be," Dumoulin wrote on Twitter.
"But now I know that I might have had a team-mate who had not been racing around clean. That is a bitter pill to swallow.”
He added: "I don't know if it's true, I hope it's not, of course. But to be honest, I would not be surprised.
"He was not the joyful Georg that I knew anymore. He came across as bitter, insecure and self-contained.
"I think it was very difficult for him to notice that he worked as hard as he could and it turned out not to be enough to make it to be the rider that he wanted to be.
"I guess those are doubts that every athlete, including me, deals with from time to time in his or her careers.
"But he turned to doping while others didn't and don't. So, am I angry? Yes!"

Tom Dumoulin Giro 2017

Image credit: Getty Images

Preidler was caught by an Austrian investigation into blood doping in endurance skiing, with evidence discovered earlier this year that alerted police to several cyclists including the former Sunweb and Groupama-FDJ rider.
"He made a terrible life decision, which also affects a lot of people around him, and he can not turn it back," Dumoulin said.
"He made a mistake and he will pay for it.
“But I don’t want to be bitter towards anyone and especially not to someone that I considered to be close to me in the past.
“I hope he will get his life back on track and that he will be able to find the joyful, nice person within him.
"I know it’s there from the first years we were team-mates and I hope he knows that about himself as well.”
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02/03/2021 AT 18:27