Haas boss Guenther Steiner believes Lewis Hamilton has no option but to stay at Mercedes for the remainder of his career.
However, the Italian has warned that it could lead to the Briton missing out on a world record eighth world championship.
Steiner told PA: “Lewis will stay at Mercedes until the end of his career. What other opportunities are out there for him? Think about that one. What other options are around? I don’t think he has many.
“He is at a stage where he is so close [to the end of his career] that doing anything different and getting used to something else would not be very positive for him. He is not happy this year because he hasn’t won a race. But he has had a lot of good years with Mercedes so he needs to stick with the people who made him.”