The Hispania team has dropped Bruno Senna for the British Grand Prix weekend, in a surprise move on the eve of the event.
Test driver Sakon Yamamoto will race alongside Karun Chandhok instead.
HRT boss Colin Kolles confirmed to the BBC that the change would take place, but further details of the driver switch will not be released until Friday morning.
Kolles added that Yamamoto only had the drive for Silverstone at present.
"A decision as to who will drive for Hispania for the rest of the season will be taken over the weekend," he said.
Yamamoto's racing debut for Hispania will mark his first Formula 1 start since his stint with Spyker in the second half of 2007.