McLaren's Spanish reserve driver Pedro de la Rosa switched over to testing duties with the Force India Formula One team at Barcelona's Circuit de Catalunya on Tuesday.
Force India this month agreed a five-year partnership deal with McLaren and Mercedes that will see them replace their Ferrari engines with a complete drivetrain (engine and gearbox) package next season.
The team will also use a KERS (kinetic energy recovery system) designed by McLaren and Mercedes.
The deal has triggered speculation the experienced De la Rosa could also be drafted in as a race driver for the Silverstone-based team but a Force India spokesman played that down.
"Pedro is an old friend of the team," he said, pointing out that the Spaniard had been a test driver for Force India's predecessors Jordan in 1998 before making his F1 race debut with Arrows in 1999.
"It's an opportunity for a fresh face to put a new perspective on an old car," he added.
While some other Formula One teams have two more tests planned before the New Year, this week's outing at the Spanish Grand Prix circuit will be Force India's last track appearance of the year.
The team will not be able to use their Mercedes engines until January and have almost used up their supply of Ferrari power units.
De la Rosa, who tested for McLaren on Monday, was joined by Force India's German race driver Adrian Sutil on Tuesday with Italian Giancarlo Fisichella scheduled to test with the Spaniard on Wednesday.
Force India's billionaire owner Vijay Mallya has said the team intends to keep Fisichella and Sutil but hinted recently that the McLaren deal could change his thinking.
"They [McLaren] will recommend what they believe to be in the best interests of my team and I have to decide," he said last week. "And I would be hard pressed to ignore their advice."