Bottas was quickest in both practice sessions at the Yas Marina Circuit on Friday, but will start Sunday's race at the back of the grid, having brought a fresh Mercedes engine to Abu Dhabi.
While putting together long-run simulations, he made a last-gasp lunge up the inside of Grosjean, who turned sharply into the corner, having seemingly not seen the Mercedes in his mirrors.
The Finn was given a reprimand over the incident, with the stewards noting: "Valtteri accepted responsibility for the collision and acknowledged that it was a failed attempt at an overtake which resulted in the collision."
Bottas said he had anticipated Grosjean spotting him, as Pierre Gasly had done a few laps earlier in a similar incident.
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"End of FP2 was a bit compromised with a minor crash," Bottas told Sky Sports, before his punishment was meted out.
"He didn't really see me coming up the inside so it's obviously my apologies, but there was nowhere for me to disappear.
"I went for the overtake and that was it. I thought he was aware I was there and maybe he didn’t look in the mirror before turning in. I expected him to see me and I saw the gap decreasing and there was no escape."
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