Sirotkin first took on the role with Renault in 2017 before he parted ways with the team the following year, as he joined Williams as a full-time driver on the 2018 grid.
However, the Russian lost his seat to Robert Kubica at the end of the season and he returned to Renault last year, where he carried out duties as its reserve driver.
Sirotkin also held the same role at McLaren, however no situation arose that required him to step into the car as a replacement.
In 2020, there is added focus on reserve drivers amid the ongoing coronavirus pandemic, as they would be required to race the car should a driver test positive for COVID-19.
“It’s great to be back with Renault DP World F1 Team as Reserve Driver,” Sirotkin said. “I know the team very well having been with them throughout the 2019 season.
“I understand the importance for a team to have a driver ready to fill in quickly should the opportunity arise, especially given the current situation the world is in.
“I’ve been keeping sharp and focused and I would be well prepared to race a Formula 1 car again. I’m looking forward to seeing my friends at Renault soon.”
Renault confirmed that Sirotkin will be present at the races this year, starting with the season-opening race in Austria this weekend.
Renault team principal Cyril Abiteboul added: “We’re pleased to welcome Sergey back to the team for this year. Given the current circumstances we find ourselves in, we must have plans in place for any situation which might occur.
“We know Sergey very well and he, likewise, knows the team. We’re looking forward to welcoming Sergey this weekend in Austria.”
Bahrain International Circuit - Winter testing