The 28-year-old will miss the race for the first time since 2012, and the first time since joining the British WorldTour team in 2015.
Viviani's absence from the race appears to go against tradition, where teams tend to pick their foremost 'home' riders for what is undoubtedly Italy's biggest race. Viviani is a Giro stage winner and 2016 omnium Olympic Champion, and therefore a high-profile figure. New recruit Diego Rosa and domestique Salvatore Puccio are Sky's two Italian riders in the race.
Confusingly, Viviani's name appeared on provisional lists for the race, even appearing on an official release regarding the 'sprinters to watch' issued by Giro organiser RCS Sport as recently as last Friday, April 21.
The reason behind Viviani's non-selection is clear: Team Sky are building a team behind its co-leaders, Briton Geraint Thomas and Spaniard Mikel Landa, with no space left for a sprinter. In such a team, a sprinter would have to fend for themselves in the bunch without a dedicated lead-out, which would be far from ideal against the likes of Fernando Gaviria (Quick-Step Floors) and André Greipel (Lotto-Soudal).
Viviani's exclusion, therefore, is a strong signal that Team Sky is very serious about this year's Giro general classification – it's the overall win, or nothing. Sky's relationship with the Giro has not been a good one: despite dominating the Tour de France and placing riders on the podium in the Vuelta a España, there has been no such consistency at the Giro. Colombian Rigoberto Uran's second place in 2013 is the team's only podium spot so far since 2010.
Although Landa's lead-up to the 2017 Giro has been steady rather than spectacular, Thomas has already shown that he is in good form, placing fifth in Tirreno-Adriatico and then winning the Tour of the Alps overall.
However, Landa has the better result in the Giro, having placed third in 2015 – which led to him being signed to Sky from Astana. Having been handed sole leadership in the Giro last year, Landa was forced to abandon due to illness on stage 10, leaving Sky with no other leadership option. Sky's race was saved with a fine stage win from Mikel Nieve, who went on to claim the mountains classification.
Thomas has not raced in the Giro since 2012, when he came 80th. Two 15th places in the past two Tours de France in the service of winner Chris Froome show that Thomas has great Grand Tour GC potential, and this year's two long time trials in the Giro play into his hands.
The Sky pair's biggest rivals will be defending champion Vincenzo Nibali (Bahrain-Merida) and Nairo Quintana (Movistar). Both have proven Grand Tour winning ability.
So Thomas and Landa are Sky's plan A and plan B (whichever way around that is), but with Viviani absent there is no plan C.
As Italian sports paper Gazzetto dello Sport's headline says, "Sky - Viviani will not be at 100th Giro. All for Landa and Thomas".
Team Sky for the 2017 Giro d'Italia: Philip Deignan (Irl), Kenny Elissonde (Fra), Michal Golas (Pol), Sebastian Henao (Col), Vasil Kiryienka (Blr), Mikel Landa (Esp), Salvatore Puccio (Ita), Diego Rosa (Ita) and Geraint Thomas (GBr).
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