Bruno Senna admits he knew Williams were going to replace him with Valtteri Bottas at the end of this season.
The Grove squad confirmed on Wednesday that Finn Bottas will partner Pastor Maldonado for the 2013 campaign with Senna left without a race seat.
The Brazilian, though, says he anticipated the move following the decision to hand Friday practice duties to the 23-year-old during 15 of the 20 races this year.
"Since the beginning of my program with Williams I accepted that I had to share the car with Valtteri Bottas in 15 Fridays as a part of his preparation for a likely debut in 2013," said Senna.
Although he finished 14 points behind Maldonado in the standings, Senna managed to pick up points in 10 of the 20 races while the Venezuelan finished in the top 10 on only five occasions.
"It has been extremely satisfying to be the team's most regular point scorer and for me to demonstrate my pace in all 20 races," he said.
"I have learned a lot and improved considerably through the season. I have had a relatively short career so far and feel as though I have come a long way in just a few years."
He added: "I would like to thank the whole team and particularly [team owner] Frank [Williams] for giving me the chance of completing my first full season in F1. It has been extremely rewarding to develop the Williams FW34 into a consistently competitive race car and cracking the challenge of the Pirelli tyres has been just one of the satisfying points."