Fabian Cancellara, the multiple world time-trial champion and one-day specialist, will miss the remainder of the spring classics campaign after suffering two fractures in his lower back.

The Swiss, one of the favourites for the Tour of Flanders and Paris-Roubaix one-day races which take place in early April, was injured during a crash at Friday’s E3 Harelbeke race, which was won by Team Sky’s Geraint Thomas in Belgium.

Cancellara was one of several riders to hit the deck when a discarded water bottle caused chaos in the peloton and, although he attempted to remount, he continued for only a few kilometres before withdrawing.

“It all happened so fast,” he told the Trek Factory website. “Someone slammed the brakes and there was no way to go, just straight into it.

“I flew over a couple of riders and then landed in a pile of bikes. There were riders everywhere. I fell so hard, and felt pain everywhere. It was sort of reflex to get back on the bike but the pain was hard, in my lower back, left wrist, and my ribs on the back.”

The 34-year-old, who has claimed seven victories in cycling’s Monuments – the major one-day spring classics – must now sit out the races in which has made his name.

“There is nothing you can do with this injury – no cast, no surgery – but just biting the pain,” he said.

Team Sky's Richie Porte assumed the race lead at the Volta a Catalunya after Alejandro Valverde won Friday's fifth stage.

Australian Porte holds a five-second advantage after Spaniard Valverde (Movistar) attacked the group of favourites to claim his second stage success of this year’s race.

Porte moved ahead of Domenico Pozzovivo (AG2R La Mondiale), while Alberto Contador (Tinkoff-Saxo) sits third overall in the race which concludes on Sunday.

Dan Martin dropped back to 10th place in the overall standings after coming home in 27th spot on the fifth stage, one minute and 35 seconds behind Valverde.

Nicolas Roche came home in 15th position and is 39th in the general classification.