Juho Hanninen has become the latest tester for Toyota's 2017-spec WRC car, the Finn also linked to one of the drives with the team next year.
Hanninen will join fellow Finn Mikko Hirvonen as a test driver for Toyota, which will make its return in the series next year.
"Juho could take part in the 2017 championship to continue to develop the Yaris," said Toyota team boss Tommi Makinen. "For this reason we will try to do as many tests as possible this year, as he will need to know the car well."
Hanninen, 35, has long been considered as one of rallying's biggest prospects but has failed to establish himself as a contender so far.
After two years in PWRC, Hanninen joined Skoda Motorsport to take back-to-back IRC and SWRC titles in 2010 and 2011 respectively.
He became a dominant ERC champion a year later and then made his debut in a WRC car with M-Sport for three rallies in 2013.
Hanninen joined Hyundai in 2014 for another part-time campaign but failed to become one of the team's full-timers.
The Finn will spend 2016 developing the new Toyota Yaris and, with the knowledge he will gain during the season, he is being considered to become one of the team's drivers next year.
Toyota is set to be the first WRC team to test its new-generation machinery, which will be revealed in April.