Paul di Resta is out of the running for a seat with Williams in 2018 despite "a very good test" with the Formula One team.
Williams are the only team in the paddock yet to announce their line-up for the new season following Felipe Massa's retirement, which left a space alongside Lance Stroll.
A host of names have been linked to the vacancy, including Robert Kubica, Pascal Wehrlein, Daniil Kvyat and Sergey Sirotkin.
Di Resta was also in the mix for a permanent drive with the British team after impressing during his sole outing in 2017, when he replaced an ill Massa in Hungary.
He will not be with the team going forward, though, after revealing Williams have informed him of their plans to look elsewhere.
"I don't think it's any secret I'm not going to be doing it," he told Express Sport. "I'm not in the plans at the moment. What else they do I don't know. They've got a few other guys in the equation.
"Sirotkin, Daniil Kvyat is out of it, Pascal was maybe cruising around: I don't know which direction they're going to go.
"Absolutely [I wanted that seat] and I was only told very, very late December that I wasn't in contention any more. I had a couple of good years there, I would obviously have wanted to do that more.
"I had a very good test when they did the 'driver assessment' if you want to call it [that]. I was very happy with how that came out.
"But for whatever reason... there are various other things that go [into getting] that seat."
Kvyat – who was demoted by Red Bull to Toro Rosso in 2016 before being dropped altogether after earning just five points last season – is out of the running after being signed by Ferrari as their development driver.
|Salah a big candidate for Ballon d´Or - Muller|
|Message from coach keeping Masters champion Reed grounded|
|Anybody can really win it - Seles feels French Open is wide open this year|
|Mambo number 5! - Non-league star channels Lou Bega hit|
|Pakistan to stop wearing smart watches after ICC intervention - Hasan|
|Saha hails ´great man´ Ferguson as legendary Man Utd boss continues recovery|
|Emery´s depth of knowledge impressed Arsenal´s Gazidis|
|Conceicao extends Porto contract|
|Lomax impresses as Saints overrun Tigers|
|McIlroy in contention at Wentworth as Bjerregaard sets the early pace|
|Bad light calls time on Thiem, Wawrinka out in Geneva|
|Garitano in, Canales out at Real Sociedad|
|Caparros accepts new role at Sevilla|
|Pliskova downed by Larsson after drawing Serena in Paris|
|They´re using the anthem as fake patriotism - Warriors coach Kerr critical of NFL|
|Lyon win record fifth Women´s Champions League title|
|French Open 2018: Doing the unthinkable - the men most likely to topple Nadal|
|French Open 2018: How can Rafael Nadal be stopped?|
|Steve Smith named as marquee player for Global T20 Canada|
|Can Emre play? Yes he Can... and so can Milner|
|Liverpool working to help fans after flight cancellations|
|Abbas and Hasan torment sorry England|
|Xavi ´thrilled´ to sign two-year Al Sadd extension|
|Holtby extends Hamburg contract despite relegation|
|Nadal begins French Open defence against Dolgopolov|
|Serena drawn to play Pliskova in French Open first round|
|FA condemns assault of match official|
|Bologna confirm Donadoni departure|
|Yates lead halved in Giro d´Italia|
|Connacht turn to Friend|
|Scotland lose injured Dunbar for June tour|
|Spalletti in ´no rush´ to sign new Inter deal|
|Ricciardo and Red Bull dominate Monaco practice|
|Mauricio Pochettino signs new deal with Tottenham|
|Pochettino signs new deal with Tottenham|
|Istanbul to host 2020 Champions League final|
|Williams sisters given French Open wildcard|
|President Donald Trump praises NFL´s anthem stance|
|Buffon in consideration for Italy call, says Mancini|
|Roberts injured in Broncos win against Eels|
|Atletico complete move for Villarreal star Rodri|
|Ozil, Gundogan not playing politics, says Low|
|Valencia complete permanent Kondogbia signing|
|Fairytale ending could be in the script, says World Cup-bound Vardy|
|Milwaukee police apologise to Bucks´ Brown over tasering|
|Television, crosswords and Nintendo - Koscielny´s remedy to World Cup heartache|
|World Cup not an audition for Barca or Madrid, says Germany star Werner|
|Neck injury rules Kohli out of Surrey stint|
|Nine LaLiga titles and 674 club games under nine managers - Iniesta in Opta numbers|
|49ers Enterprises takes stake in Leeds United|
|Manchester United should sell Pogba if he´s unhappy - Scholes|
|Andres Iniesta´s nine LaLiga triumphs with Barcelona|
|Andres Iniesta: The footballers´ footballer|
|Real Madrid v Liverpool: Salah has foundations in place for Ballon d´Or challenge|
|Iniesta´s Vissel Kobe move confirmed|
|Low upbeat over Neuer´s World Cup hopes|
|´No secrets´ in playoffs, says Celtics rookie Tatum|
|Real Madrid v Liverpool: Salah takes his chances better than Ronaldo - Opta|
|Cubs, Yankees find very different ways to lose|
|Cole hoping to see Rooney in MLS amid DC United links|
|LeBron feeling worn down following Cavs loss|
|Rahm enjoys ´traditional golf courses´|
|Upbeat Spieth eyeing first win of 2018|
|Ovechkin leads Capitals into Stanley Cup Finals|
|Federer: Serena may be the greatest of all-time|
|Copa Libertadores Review: Gremio top group, River and Flamengo draw|
|Celtics rebound with key game-five win over Cavs|
|Warriors duo Thompson, Iguodala questionable for game five|
|Suarez: Iniesta hard to replace at Barcelona|
|Slipper suspended after positive cocaine test|