Mercedes have confirmed that Pascal Wehrlein will no longer race under the Silver Arrows' umbrella in 2019, potentially offering the German a route back into Formula 1 with Toro Rosso. The Red Bull-owned team have refused to sign Mercedes-backed drivers, but Wehrlein's free-agent status could appeal.
Daniil Kvyat is expected to return to Toro Rosso in 2019, while Brendon Hartley has admitted he is still fighting for his F1 future after an underwhelming first full season.
Wehrlein raced for Manor and Sauber in 2016 and 2017, having becoming the youngest champion in DTM history in 2015, but he has not been able to make the grade for the Silver Arrows in F1.
Mercedes team principal Toto Wolff confirmed that Wehrlein was being released in order to further his career, having moved back to DTM in 2018.
He said: "Unfortunately, we couldn't offer Pascal a competitive drive for next year.
"In his best interests, we have therefore decided together with Pascal not to extend our agreement and to give him the best chance of securing an opportunity elsewhere that his talent merits.
"We want to thank him for his fantastic performances for Mercedes-Benz in recent years and wish him all the best for the future."
Dr Helmut Marko has said that 10 drivers are in his thoughts for a seat at Toro Rosso and Wehrlein suggested that wheels were in motion to secure a deal away from Mercedes.
"My contract with Mercedes expires at the end of the 2018 season and we have jointly decided not to continue further together," he said.
"I am looking for new challenges and opportunities, and am currently talking to other teams about a cockpit for next season."