Cape Town - Just as Sauber have found their feet, Marcus Ericsson has been shown the door in what he has billed as "obviously disappointing" timing.
The Swede joined Sauber in 2014 and has been with the team through tough times including a point-less 2016 campaign.
This year, though, having joined forced with Alfa Romeo, Sauber are very much on the up.
The team has managed 36 points compared to last year's five and sit eighth in the championship.
More gains are expected next season but Ericsson won't be racing, only a test driver, with Kimi Raikkonen and Antonio Giovinazzi leading the charge.
"Of course, it was hard to accept," Ericsson told Autosport.
"I thought I was going to stay but obviously I understand the reasons as well, with a driver like Kimi becoming available, and the other seat is obviously taken [by Ferrari].
"To get an opportunity to get a driver like Kimi, it's impossible to not take that opportunity.
"So I understand that, even though it's obviously disappointing for me and my career.
"I feel like I've been here, working so hard for the team in very tough times, and the car has been at the bottom, and people have been leaving the team, and I've been always putting all effort into trying to turn it around, staying positive and never blaming the team for anything.
"[I've] just been pushing really hard to try and help the team to improve and I feel like I've been very much part of that journey and part of that process.
"And to then not be able to continue that, when the car is finally getting competitive and the team is finally getting competitive, it hurts a bit, but that's the sport we're in."
Ericsson is off to IndyCar next season where he will race for Schmidt Peterson Motorsports.
"Just the thought of going to a race and knowing that I can win this weekend, it just gets me so excited, because I've missed that so much," Ericsson said.
"All my career [before F1], every weekend, it's been about trying to win, and then for five years you don't even have that thought in your head. It's not even in your head.
"And now, when I've accepted that F1 is not going to happen next year, it's something that really gets me excited - that next year I could actually go to the first race and know that, if I do a a good job, I can actually win."