Max Verstappen Red Bull F1 move eases Toro Rosso "unrest" with Sainz

Marko has also claimed Daniil Kvyat's return to Toro Rosso to make way for Verstappen was in order to ease the growing pressure on him following his poor start to the year.

In light of the unrest between Verstappen and Sainz at Toro Rosso, and with Kvyat's collisions with Ferrari's Sebastian Vettel in Russia on Sunday, Marko felt the time was right for the duo to swap seats.

Explaining the switch, Marko told Motorsport-Total.com: "It was primarily a measure to take away the pressure off Daniil.

"This year he has not been near the same performance as last year.

"He has been on average three to five tenths [of a second per lap] slower than [team-mate Daniel] Ricciardo. Last year he was at eye level.

"He has been very inconsistent, had many ups and downs, and the crash in Sochi was as a consequence of the internal pressure he had built himself. It did not come from us.

"Romain Grosjean was once in a similar situation when he had crash after crash.

"We wanted to avoid that, and our luxury is we have the ability to set him up for Toro Rosso again.

"On the other hand there has been considerable unrest at Toro Rosso between Verstappen and Sainz, so we have solved several internal problems.

"And we have not removed Kvyat. He is still with us in the squad, and Toro Rosso is a good midfield team."

Suggested to Marko Verstappen's move was a timely one given Ferrari has long been interested in the 18-year-old, he replied: "As you know we have long-term contracts so there was no need for action.

"But now we have Ricciardo and Verstappen side by side, and we can accurately assess how the two perform, and we have Kvyat against Sainz.

"This makes future decisions easier, but as mentioned, all four drivers have long-term contracts."