Lewis Hamilton's father says Valtteri Bottas may have made a career-ending decision in joining Mercedes for the forthcoming Formula One season.
Bottas will swap Williams for the Silver Arrows in 2017, filling Nico Rosberg's seat following the world champion's shock post-title retirement.
Last season was just the second in Hamilton's 10 campaigns in F1 that he was beaten by a team-mate.
And Anthony Hamilton has backed his son to roar back after missing out on a third straight title in 2016, with Mercedes once again well-fancied to master new regulations in F1.
"Anybody who goes up against Lewis needs to have planned their career correctly because it could be a career-ending move when you go up against Lewis," Hamilton Senior told Sky Sports News.
"I personally think, while he's getting older and more mature, he's still actually heading towards the prime of his career. So Lewis is going to be a force to be reckoned with this year."