American driver Alexander Rossi has returned to Manor in a reserve driver role for the 2016 season.
Rossi raced for Manor in five of the last seven races of 2015 but lost out on a full-time drive this year to Indonesia's Rio Haryanto. The 24-year-old has already signed up for his rookie Indycar season with Andretti Autosport, meaning he will combine duties this year.
"I've invested most of my career in F1 and I'm not one to kick my heels and wait for things to happen, so this is my way of staying sharp and prepared," Rossi said. "It was disappointing to miss out on a race seat with Manor Racing this year; everyone knows I pushed and worked hard for it. As Official Reserve Driver though, I have a very complimentary dual program at the highest level of motorsport.
"IndyCar Series is the premier category of open wheel racing in North America and extremely competitive. I also have the privilege of racing with a championship winning team, Andretti Autosport. I'm confident this experience will add to my role as a very important cog in an F1 team's wheel."
Manor's announcement says Rossi will be "the first driver to perform simultaneous IndyCar and F1 roles". Rossi will attend 11 races, five of which occur during the IndyCar season. His first will be the Russian Grand Prix in May and his job will be "to work with the engineers and drivers to help develop the MRT05".
Manor boss Dave Ryan said: "We're very fortunate to have someone of Alex's calibre in the role of Official Reserve Driver. The fact that he's racing full time in the IndyCar Series this year was simply a challenge to be overcome; something we're pretty good at. We need a safe pair of hands for the role, which always carries the potential to have to step up to race, but also someone who can really contribute to the development of the car. For Alex, F1 is still unfinished business.
"He did a great job when he drove for us in five of last season's races and he's a highly rated and valuable part of our line-up. He does have one heck of a schedule ahead of him and it's a commitment that only the most disciplined of drivers would be able to manage. We're confident he's the man for the job."