Toto Wolff has said it is important for Mercedes to consider many driver line-up options for next year and 2019 given Nico Rosberg's shock retirement.
Mercedes are expected to keep Valtteri Bottas as Lewis Hamilton's team-mate for the 2018 season, but the Brit's current deal would need to be renewed for the 2019 campaign and beyond.
"There is certainly a component that in F1 you need to have a fall-back solution, a plan B," Wolff told Motorsport.com.
"Even having a contract doesn't necessarily mean that everything is going to be like it is. There could be a change of circumstances.
"What we have now is a plan A, and then there is obviously various possible plays afterwards, because the driver market changes a lot in 2018 and 2019. It is important to consider plan B and C."
As for the 2019 puzzle, Wolff admitted it is going to be a difficult one to solve.
He added: "It is very complex. There are many possibilities where a driver could end up.
"There are certainly at least a handful of capable drivers who would perform in a Mercedes. So you have to consider all scenarios."