Vinales left Monster Energy Yamaha ahead of schedule last month and had two successful test days with Aprilia at Misano this week.
Aprilia on Wednesday revealed that the 26-year-old will line up alongside Aleix Espargaro in the next MotoGP™ round on home soil this week.
Savadori, who is recovering from the fractured right malleolus he suffered at the Styrian GP, will take part in a selection of wildcards this season and be an Aprilia test rider next year.
Aprilia Racing CEO Massimo Rivola said: "We are extremely proud to be able to announce our plans for the current season and for 2022 with the goal of optimising the contributions of our three riders to the utmost.
"Alongside our confirmed rider, Aleix, it is our pleasure to welcome a talented athlete like Maverick to the Aprilia Racing team, who demonstrated a great feeling with the team and the bike straight away and who I am confident will be able to give his best as early as the Aragon GP.
"At the same time, we are also confirming Lorenzo’s role as 2022 test rider.
"This is a fundamental position that rewards the great efforts he has demonstrated in developing the new RS-GP, whereas he will finish out the 2021 season taking advantage of the wildcards that we'll decide on together as soon as he is back to 100 per cent fitness."
Romano Albesiano, Aprilia Racing technical director, said: "The decision to have Maverick on the track from Aragon is a direct result of the tests done in Misano.
"It was not a given that, after a career spent up to now on a bike with an in-line engine, Maverick would have a good feeling with our V4 straight away. This is why the test on this track, historically not an easy one for our bike, was an important moment of assessment.
"Therefore, we are satisfied with Maverick's immediately positive reactions, which demonstrated a good feeling both with the RS-GP and with the team and our work method.
"His and Aleix's talent, combined with the experience Lorenzo has gained this season, make us optimistic about the future of our MotoGP project."