Brazilian Bruno Senna, nephew of the late great Ayrton, has been dropped by his HRT Formula One team for Sunday's British Grand Prix.
"The drivers are (reserve Sakon) Yamamoto and (Karun) Chandhok," team principal Colin Kolles told Reuters in the team motorhome on Thursday.
"There is nothing more to say. This is it at the moment. We will make a press release."
A spokeswoman for the governing International Automobile Federation (FIA) confirmed that Japanese test driver Yamamoto and India's Chandhok had been entered for the weekend, and not just Friday practice.
Kolles would not say why Senna had been dropped but there was speculation in the Silverstone paddock that a lack of sponsorship was the cause.
Spanish-based HRT, also known as Hispania, are one of three all new teams entered this season and are fighting a financial battle as well as one on the track.
The team have little hope of scoring so much as a point this season, with just finishing races their main priority.
Senna has been classified in just three of his races so far, with a best result of 16th in Malaysia and China.
Yamamoto, who can count on financial backing, started 14 races in 2006 and 2007 for now-defunct Super Aguri and Spyker -- then run by Kolles -- without scoring a point.
Senna had been looking forward to competing at Silverstone, a circuit he considered a second home and where he secured pole position while racing in the GP2 and Formula Three support series.
"I love driving at Silverstone," he said this week. "It's a unique place and and feels like my second home grand prix. The atmosphere is great, with so many fans turning up for the race, and I have always been fairly successful here."
The driver and his management were not available for comment.