But the timetable would allow her to double up and - as the defending 200m champion - Felix already has a wildcard entry for that event so could concentrate on the 400m at the tough US Trials.
Talking of which, Ohuruogu has the 400m wildcard so Britain are entitled to have three other women in that event in Berlin.
Nicola Sanders and Lee McConnell already have the 'A' standard of 51.50 seconds, so in theory UKA could select another woman provided she has at least reached the 'B' standard of 52.30.
YAMAUCHI SET TO STEP UP
Yamauchi has finished in the top 10 at the last Worlds and the Olympics
Like Ennis and Ohuruogu, Mara Yamauchi is an athlete who need not provide any more evidence to prove she can be a contender in Berlin.
She has already been selected for the World Championships following her second place in the London Marathon.
There, she defeated all three Olympic medallists and matched strides with the Berlin favourite Irina Mikitenko for much of the race.
She was ninth at the Worlds in Osaka in 2007 and sixth in Beijing. Could this be her year?
OTHER GB CHALLENGERS
When you add in Tasha Danvers - who has just defeated Olympic champion Melaine Walker - and our relay squads to the mix, the record British woman's medal count of four from Osaka in 2007 seems perfectly possible.
Jackson is Britain's best race walker by far
While perhaps not in line for Berlin medals, I would like to give honourable mentions to Johanna Jackson and Eilidh Child.
Jackson, 24, is far and away our best race walker and has improved her British 20km record already in 2009.
Twenty-two-year-old Child - whose first name is pronounced "A-lee" - clocked a stunning 55.52 sec to win the 400m hurdles at last month's Inter-County Championships.
That moved her from 26th to eighth on the British all-time list and took her to the brink of a World Championship 'A' qualifying standard.
With Danvers, Child, Perri Shakes-Drayton and world junior medallist Meghan Beesley, the women's 400m hurdles is going to be one of the most exciting events in Britain this year.
It is an event Britain will expect to dominate at the European Team Championships in Portugal - the first big test for UK athletes in this World Championship year.
British women in 2009 World top 20 in World Championship events (as at June 1):
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