Kenny Elissonde will replace the 23-year-old Welshman at the first race of the WorldTour season, which starts on Tuesday (January 17) in Adelaide, Australia.
Doull was rested from the People Choice Classic prelude criterium on Sunday as a precaution ahead of the race. However, he still has not sufficiently recovered in order to take part on the TDU.
A Team Sky spokesman said the Olympic team pursuit gold medallist was suffering from a stomach bug.
He is due to stay in Australia for the duration of the race, and train once he recovers.
Elissonde joins Geraint Thomas, Ian Stannard, Luke Rowe Sergio Henao, Sebastian Henao and Danny van Poppel for the six-stage race.
American team Cannondale-Drapac also confirmed that New Zealander Tom Scully will replace Australian Brendan Canty in its line-up for the TDU. Canty is reportedly suffering from flu-like symptoms.