Valtteri Bottas risks watching his F1 career stagnate at Williams, fellow Finn Heikki Kovalainen has warned.
Earlier this year, the now 26-year-old Bottas was a strong candidate to replace Kimi Raikkonen at Ferrari for 2016.
The Maranello team, however, ultimately re-signed the 35-year-old Finn, leaving Bottas to spend his fourth consecutive season in formula one at Williams.
Former F1 driver Kovalainen, whose own career stagnated at Caterham following earlier stints at Renault and McLaren, commented: "Valtteri is still young. I see him on a good path.
"He has all the potential to become world champion. But whether he can do that at Williams is hard to say," the 33-year-old, now racing in Japan’s premier GT series, told the Finnish broadcaster MTV.
"Valtteri eventually needs to get into a car that can win the championship, and if that doesn’t start to happen beyond next year, he could lose the momentum.
"It is then hard to get back from that," Kovalainen added.