The Lotus reserve driver, who won the GP2 title in 2012 but has not raced since, says he accepts the team's decision but that it was surprise when Heikki Kovalainen landed the seat instead of him.
"When they told me that they could not sign Hulkenberg, I was almost convinced that they were going to choose me but they called Kovalainen because they thought that he was a better choice," Valsecchi told AUTOSPORT.
"For my career it's not something fantastic because I've been working for the team all season long and then when there was the time to drive, I missed my chance.
"But it was the team's decision that with two races left they still had the chance to beat Ferrari [and Mercedes] in the championship and they decided to take Kovalainen instead of me, so we need to accept it."
Valsecchi believes that while Kovalainen was the safe choice, the fact he had more to prove might have given him the edge.
But he accepts Kovalainen's record made the choice an understandable one even though he is confident he would have been able to do the job.
"Maybe choosing Kovalainen was the most safe decision," said Valsecchi.
"He won one race with McLaren, he was really competitive at that time and in the last few years he was racing with Caterham and was always more competitive than his team-mate, so I can understand the choice," he said.
"But I was thinking that they were going to choose me for the motivation and the aggression I have to turn up in the right way [and perform] for my career."
The Italian added that he has not given up hope of being given a chance, stressing that he would be ready to jump into the car for next weekend's Brazilian GP.
Although this is unlikely as Kovalainen has been confirmed as Raikkonen stand-in for the final two races of the year, Valsecchi remains committed to his reserve driver role.
"What I am sure of is that I am ready and maybe if they need me for Brazil, I am happy to deliver a good result in the points," said Valsecchi.
"If they give me a small chance, I will use it as I have the determination to use it and just want to say that I am ready whenever they need me.
"Life is strange, things can change quickly and maybe for Brazil they will ask me to do something."