Esteban Gutierrez sounded upset on Friday after missing the opportunity to make his formula one race debut.
The Mexican teen was signed by Sauber to be the Swiss team's official test and reserve driver at all races in 2011.
But the reigning GP3 champion, who now races in the F1 support category GP2, was not in Canada on Friday when his countryman Sergio Perez had to withdraw from the event due to illness.
Instead, Sauber turned to in its 2010 driver Pedro de la Rosa after hurried negotiations with McLaren, who now employ the veteran Spaniard as its reserve driver.
Despite Perez's hospitalisation, concussion and bruised thigh in Monaco, and the fact FIA doctors only cleared him to race on Thursday, Sauber was caught so unprepared that de la Rosa was wearing McLaren overalls when he took to the C30 in afternoon practice at the Circuit Gilles Villeneuve.
And Gutierrez, apparently in his native Mexico, wrote on Twitter that Sauber displayed a "lack of transparency" in informing its official reserve of the situation.
I never received any instructions to prevent this situation. I was ready
"I learned from Twitter," he said on the social networking website.
"It's a shame to hear about Montreal, I hope 'Checo' (Perez) recovers soon," added Gutierrez in Spanish.
"I never received any instructions to prevent this situation. I was ready," he said.