The 29-year-old Trek-Segafredo rider withdrew from the French race after stage five from Salon-de-Provence to Sisteron. He placed 130th on the stage in a group that came in over 11 minutes down on winner Jérôme Cousin (Direct Energie).
Trek-Segafredo announced Degenkolb's abandon via Twitter, saying: "Unfortunately @johndegenkolb suffers from bronchitis and won't take the start in stage 6 tomorrow."
Degenkolb himself said: "It was a difficult decision but I cannot take health risks now, with my big goals coming up. But no worries, I will be there to 'chase aces'."
On Monday, March 5, Degenkolb said on his own Twitter account that he was not happy with his performance on the opening two days of Paris-Nice, saying: "Honestly, I am not happy with the results of both stages, not at all. I was always ways too far behind in the final. We have to do much better tomorrow and the next few days."
Degenkolb has already taken two victories this season, claiming two wins in the four-race Challenge Mallorca in late January.
He won Milan-San Remo and Paris-Roubaix in a successful 2015 season, but could not defend either race in 2016 after being involved in a training incident where he was hit by a car and nearly lost one of his fingers.
Degenkolb bounced back in 2017, with a strong of top 10 places in the Classics, including fifth in Ghent-Wevelgem, and seventh in both the Tour of Flanders and Milan-San Remo.
With the flatter stages over, the remaining three stages of Paris-Nice are more for the climbers and general classification riders than sprinters.
Several other riders abandoned the race before or during stage five, including stage two winner Dylan Groenewegen (LottoNL-Jumbo), French sprinter Nacer Bouhanni (Cofidis) and British rider Dan McLay (EF Education First-Drapac).
Currently, Spaniard Luis Leon Sanchez (Astana) leads Paris-Nice with a margin of 15 seconds over Team Sky's Wout Poels. The race concludes on Sunday, March 11.
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