When reserve driver Felipe Nasr made his first Friday appearance in 2014, it was at the wheel of Finn Bottas' car in Bahrain.
Then in China, Bottas once again sat out the session rather than his teammate Felipe Massa.
And it is believed that when Susie Wolff steps into the FW33 on the Fridays at Silverstone and Hockenheim, once again it will be Bottas on the sidelines.
"It is just the agreement we have," Bottas explained to Finland's MTV3 broadcaster.
"One agreement allows it, and one does not," he added, obviously referring to the contracts in the hands of Williams' 2014 race drivers, Bottas and Massa.
Bottas, however, is not bitter about the situation, as he enjoyed the very same kind of treatment in 2012, when he regularly stepped into a Williams on Fridays.
Back then, it was race regular Bruno Senna who always had to step aside for Bottas.
"Of course, every young driver wants to drive whenever you are given the opportunity," Bottas said in Barcelona.
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