Those of us who wish to see Robert Kubica in Formula 1 again can lower our signs and go home because it looks like this is the end of the road for Kubica. Motorsport Italy reports that Sergey Sirotkin, Kubica's main rival at the post-season Abu Dhabi test, is now the most favorable of Williams' driver candidates, due to financial backing from Russian bank SMP. It is reported that the 22-year-old Russian driver's signing will be announced sometime next week. Live GP Italy corroborates Motorsport Italy's report that Sirotkin will have the seat, citing its own source.
So, why did Williams elect the young Sirotkin over fan favorite Kubica? Aside from the reported cashflow problems the team is undergoing, which force its driver candidates to compete with sponsorship packages, qualifying pace and performance on the Pirelli tires was an issue for Robert, according to the BBC Sport's Andrew Benson in an interview with Polish sports outlet Sportowy Fakty.
"The problem of the Pole is primarily speed on qualifying laps, during which the car has a small amount of fuel in the tank," said Benson to Sportwowy Fakty, in the translated interview, "Kubica [...] could not significantly improve performance. I also received information that the 33-year-old himself revealed to his stable directors [sic] his problems with adapting to the new tires provided by Pirelli."
As was stated repeatedly by team personnel and myself last year, Kubica's fitness was not a deciding issue in Williams' driver selection. Performance is the only official metric that Williams will use to select its drivers, but BBC Sport's Andrew Benson reports that Kubica's pace on Pirelli tires is not the only offering inferior to that of Sirotkin—his sponsor bundle is coming up short, too.
The Drive contacted Williams for comment upon the story, but a spokesperson declined to comment, stating, "media have speculated all the way, saying 'next week' every week since November. [...] As before, we have no comment until we have an announcement to make."