Cavendish has raced every edition of La Classicissima since winning on his debut 10 years ago, but has endured a complicated couple of years due to Epstein Barr Virus.
The 33-year-old took an extended break in the second half of last year after the virus came back for a second time, and has been easing his way back into racing in 2019. After finishing the Vuelta a San Juan and UAE Tour, where he primarily worked for teammates, he suffered a setback at Paris-Nice last week as he struggled in the crosswinds and abandoned on stage 2.
Cavendish is clearly some way short of full strength, as he was absent from the seven-man team for Milan-San Remo announced by Dimension Data on Thursday.
"The race was just his third back," DS Rolf Aldag said after Paris-Nice, "following already tough outings at the Vuelta a San Juan and the UAE Tour, as he continues to work his way back towards full fitness following a long lay-off from racing due to illness last year."
Dimension Data will instead be led by Nizzolo, who himself has had a complicated couple of seasons through injury. Knee surgery in the winter, however, seems to have put an end to that, and he already signalled a return to form with victory on the final stage of the Tour of Oman. Crashes scuppered the Italian at the recent Tirreno-Adriatico, where he finished fourth on stage 3 behind Elia Viviani, Peter Sagan, and Fernando Gaviria.
Nizzolo will be hoping to survive the climbs in the late portion of the 291-kilometre race, including the Cipressa and Poggio, and to take part in a bunch sprint on the Via Roma.
"Milan-San Remo is always a special race because at the start there are at least 50 riders who can play the game for the victory," said Nizzolo.
"It’s not a really hard race, if you take into account its profile, but after 290km every small hill can feel like a big, big climb. So we will try to spend the least energy as possible and be ready for those crucial final stages."
Dimension Data have back-up in the form of Reinardt Janse van Rensburg, while the team is rounded out by Enrico Gasparotto, Tom-Jelte Slagter, Roman Kreuziger, Steve Cummings, and Bernhard Eisel.