Ribeiro, who had indicated her general fitness for the marathon distance by recording 68min 44sec for a half-marathon in March, pulled up in pain while running on Tuesday. She is suffering from patella tendinitis.
The Portuguese runner had been making desperate efforts to recover from a different injury sustained 10 days earlier, when she completed a 30- kilometre run suffering from pain in the back of her knee. She had been receiving twice-daily treatment.
Ribeiro, whose first attempt at the 26 miles 385 yards distance had been keenly awaited, was 4-1 second favourite for the women's title behind Joyce Chepchumba of Kenya, who won the title in 1997 by a margin of one second from Scotland's defending champion, Liz McColgan.
It is the second big disappointment for the organisers of the Flora London Marathon, who announced last month that Catherina McKiernan of Ireland would be unable to defend her title because of an Achilles tendon problem.
Britain's Paul Evans says Sunday's race is wide open. But the former Chicago champion has a sneaking fancy an old friend, the South African Olympic champion Josiah Thugwane, could be first across the line.
Eliminated by injury from a race he desperately wanted to contest, Evans turned to the role of tipster when Thugwane and the marathon world record holder, Brazil's Ronaldo da Costa, appeared at a London press conference.
And taking time off from his 38th birthday celebrations, Evans suggested Thugwane, who dropped out of last year's race after sustaining a hamstring injury when trying to avoid a wheelchair competitor, will make amends this time.
Evans said: "I've heard Thugwane's training preparations have been going really well. You cannot doubt his toughness and determination, and I really do fancy him.
"Mind you, any four or five could win it, including Jon Brown. It would be great for Britain if he did."
Thugwane shot from obscurity to national hero when becoming the first black South African to win an Olympic gold medal three years ago.Reuse content