Red Bull Motorsport Advisor Helmut Marko has revealed the reasoning behind dropping Nyck de Vries after only 10 races into his rookie F1 season.
The Dutchman was under pressure following a difficult start to his time in the sport and after finishing last of those still running at the British Grand Prix, Daniel Ricciardo was announced as Yuki Tsunoda's teammate at AlphaTauri for the rest of the season.
It brings to an end an underwhelming stint in F1 for a driver that had marked himself as a force to be reckoned with during title-winning campaigns in F2 and Formula E, as well as strong performances in the World Endurance Championship.
Referring to de Vries' points-scoring Williams substitute appearance last term, Marko told de Telegraaf: "We signed Nyck because he performed great at Monza last year."
"We expected him to be at least equal to his teammate this year, but that wasn't the case. Actually, he was always three-tenths slower. We didn't see any improvement.
"He is 28 years old, has a lot of experience and also a lot of knowledge as a test driver in various F1 cars. I don't think you can compare him to a young rookie.
"At the end of April in Baku, he started the weekend well and I thought he was going to perform better, but then he crashed again. Unfortunately, he never once did a super lap that amazed us."
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'Why should we wait'
The decision to change two races before the summer break comes across as harsh as well as curious, with Ricciardo now thrust back into a seat less than a year after being dropped by McLaren.
On why Red Bull and AlphaTauri reacted so quickly to make the switch, Marko insisted: "We had to do something.
"Why should we wait and what difference do two more races make, if you don't see any improvement? Nyck is a very nice guy, but the speed just wasn't there."
Regarding de Vries' future in F1, the Austrian added: "That will be difficult, I think. But at the same time, I think he saw this coming. He can build a great career in long-distance racing."
Ricciardo's promotion came on the day he stepped back into an F1 car for the first time as Red Bull's third driver as he took part in a Pirelli tyre test.
"His lap times were competitive on three different tyre sets," explained Marko.
"If Ricciardo hadn't had the speed, we would have considered something else. But AlphaTauri is not in a good position, last in the constructors' standings, so we have to do something to bring something about.
"That often happens after a driver change, Ricciardo brings new energy to the team."