Mercedes boss Toto Wolff revealed Fernando Alonso could be an option for the team if they are unable to negotiate a new deal with Nico Rosberg.
Rosberg is reportedly out of contract at the end of the 2016 Formula One season after having signed a "multi-year" extension in 2014.
Wolff said it was a "priority" to tie championship-leader Rosberg to a new deal, but admitted they will consider Alonso should the German driver decide to leave.
"Fernando is one of the best drivers in history and I like his character, but our priority now is Nico," Wolff told El Mundo.
"If [Rosberg] does not want to renew, then we will consider other options, like Fernando.
"[Alonso's] age is not a problem - his speed and his motivation are still there."
Wolff also revealed Alonso held talks about joining Mercedes two years ago before the Spaniard signed with McLaren after five years at Ferrari.
"Fernando explored his options and one of them was Mercedes," he added.
"He spoke to us, but we could not negotiate as we promised Lewis [Hamilton] that while we tried to renew his deal we would not talk with other drivers and we did not."