Ohuruogu, 33, who won gold at the 2008 Games and was twice world champion, failed to qualify for Sunday's final, finishing a disappointing third in her heat.
She has said she would be available if required to compete in the 4x400-metres relay at the London event, starting on Aug. 4.
Also in danger of missing out is Britain's third-fastest sprinter of all time, Chijindu Ujah, who faces an agonising wait to see whether he will be picked as a selectors' choice after pulling out moments before his 100-metres final in Saturday's qualifiers.
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Ujah, who had won his semi-final heat in 9.98 seconds, withdrew from the final with cramp, leaving Reece Prescod and James Dasaolu to take the two guaranteed places in the squad.
The final place is likely to be between Ujah and Adam Gemili, who has competed in an Olympic final.
European champion Dina Asher-Smith finished sixth in the women's 100-metres on her return after suffering a broken foot, and looks unlikely to make the championships in that discipline, although she may still make the 200-metres and sprint relay events.
(Reporting by Neville Dalton; Editing by Toby Davis)
