How so? I just don't see it.
Red Bull top brass obviously didn't want him, even though he outperformed both Daniel and Liam last year. He can't really do any worse than Liam did, and people are already pointing the finger at the car.
Yuki's career wasn't going anywhere with junior Racing Bulls team, he's been stuck there for 4+ years. Furthermore, Honda has his back. So even if he does lose his RB seat by underperforming, Honda will probably pay Aston Martin to eventually give Yuki a seat with them or at least be their backup driver.
On the upside, if he performs well, he has everything to gain.