Sagan was stunningly thrown out of the Grand Tour after being deemed to have endangered fellow riders when he stuck out an elbow that contributed to a fall at the conclusion of stage four that left Mark Cavendish in hospital.
Lotto-Soudal manager Marc Sergeant claimed Greipel was furious with Sagan for his actions in Vittel immediately after the stage.
“He was quite p****d [off] by the attitude of Sagan, making some moves which he shouldn’t make,” Sergeant told Eurosport.
“Yesterday it was the same thing in the intermediate sprint, he gave an elbow to Andre and he [Greipel] was a little bit p****d [off] yesterday already.
“Twice in a row is too much. Greipel was saying, ‘He isn’t my friend anymore from now on’.”
But it appears the German sprinter has tempered his stance after reviewing footage of the incident that has cost five-time points classification winner Sagan his place at this year’s Tour.
Greipel wrote on Twitter: “Sometimes I should watch images before I say something. Apologies to @petosagan as I think that decision of the judge is too hard.”