Simon Clarke sustained three broken vertebrae in a crash at the Milan-San Remo on Saturday, while Andre Greipel will undergo surgery on a fractured collarbone.
Education First-Drapac rider Clarke and team-mate Daniel McLay went down after a touch of wheels on the Capo Berta, failing to cross the finish line as Vincenzo Nibali triumphed in the first Monument of the season.
In sodden conditions, the Australian, who topped the mountains classification at the 2012 Vuelta a Espana, suffered a serious back injury as a result.
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Clarke posted on Twitter: "Unfortunately I have 3 broken vertebrae from my crash in MSR today.
"On the bright side, enjoying a pizza in the back of the ambulance."
Lotto Soudal rider Greipel also faced a trip to hospital after a crash on the descent of the Poggio - where team-mates Jasper De Buyst and Jens Keukeleire also fell.
Greipel wrote on Twitter: "Unfortunately not the way I wanted to finish my @Milano_Sanremo. 2 crashes and the last one 4 km from the finish let our amazing @Lotto_Soudal teamwork not getting [sic] the result we worked for - now off to surgery for my broken collarbone."