Dowsett crashed while training near his home in Essex on Tuesday. X-rays confirmed that the 26 year old had fractured his collarbone.
The severity of Dowsett's fracture will require surgery, which the Briton will likely undergo on Thursday.
Dowsett was one of many riders, alongside Australians Rohan Dennis and Jack Bobridge, who have their sights set on the UCI Hour Record.
Due to his injury it is uncertain whether Dowsett will still undertake the challenge scheduled for 27 February.
Budget Forklifts' Jack Bobridge will make his attempt on 31 January in Melbourne with BMC's Rohan Dennis taking up the challenge in Switzerland in February.