Mercedes motorsport boss Toto Wolff has finally confirmed Esteban Ocon will be the team's official reserve driver in 2019.

The writing has been on the wall for a while for the Frenchman, who'll be dropped by Force India after Sunday's race in Abu Dhabi and replaced by Lance Stroll for next season.

A final chance was possible at Williams but after Robert Kubica was announced on Thursday, Wolff finally took the chance to make the 22-year-old's future clear.

"He is going to be pretty close to the Mercedes team - he will be our reserve driver and third driver," he said in the team principals press conference.

"We hope to do the odd test with him, we are looking at pre-season and in-season but it's not sorted out yet.

"He will do a lot of time in the simulator to make sure that he is ready."

Ocon is expected to return to F1 as a race driver in 2020 and most expect that seat to be at Mercedes replacing Valtteri Bottas, who again played down the situation on Thursday.

As part of his role, however, Esteban could find himself also driving the Force India or Williams at some point next year as a reserve with the latter potentially offering more.

According to Sky Sports during Friday practice, Williams are keen to have a third driver on standby in case of an unexpected situation with Kubica's arm.

Some questions remain over his mobility at a circuit like Monaco, however, the Pole has previously insisted everything should be OK.