Robert Kubica will leave Williams at the end of the 2019 Formula One season, the British team announced on Thursday.
Kubica made a sensational return to F1 with Williams, seven years after partially severing his right arm in a crash at the Rally of Andorra in 2011.
The Pole initially returned as a test driver in 2017 and then reserve driver for the 2018 season before making his full return on race weekends this year.
However, the 34-year-old has grown frustrated with Williams' inability to compete. Kubica has taken Williams' sole point of the 2019 season after 14 races as they languish at the bottom of the constructers' championship.
"I would like to thank the team for the last two years and for helping make my comeback to the Formula One grid possible," said Kubica.
"But I feel that the time is now right for me to move on to the next chapter in my career."
Kubica has not ruled out continuing in Formula One but told the BBC it would not come "at any cost."