Ferrari are the only ones without a presence in the official F1 esports championship, which is in its third season and involves the teams only later in the year.
His place was taken by Italian Riccardo Musconi, previously Hamilton's performance engineer.
It's clear Bottas is performing at an extremely high level and Hamilton has a serious title contender across the garage from him.
A Brazilian-Austrian flag will be displayed on the podium in tribute to the late triple champion Ayrton Senna and Roland Ratzenberger who died at Imola in May 25 years ago. "That's to be expected, the little bit of a step that he's taken".
"So when (team boss) Toto (Wolff) mentions glimpses of that, he has seen a glimpse of it, but what's really important is that we pull together as a team. It is not as strong as something that has been built over six years". "I am much stronger in and out of the vehicle and much better at knowing how to manage my relationships", he said, dismissing any thought of a breakdown in relations with the mild-mannered Bottas. "It's only been four races, so just watch this space". "Everything is still very much up for grabs this season and we will be keeping our foot firmly to the floor". "In the second run I had to try something different and it didn't work".
Bottas's ninth career pole position is his first in Spain and his third in a row this season, further reinforcing the immensely strong start the Finn has made.
"We are happy, engine-wise", said Vettel, unfussed at trailing Mercedes again. "So, so far, so good".
At Mercedes, the difference the upgrades made was more obvious in lap time, although Hamilton complained of a different balance.
Valtteri Bottas and Lewis Hamilton have swept the top two spots at the first four races of the year, and Mercedes have also won the Spanish GP in all but one of the last five seasons. But Hamilton and Bottas were still faster than their Ferrari rivals.
"There are things that happen in the background that you won't know, and I don't really feel this is the place to talk about it", Hamilton said yesterday at the Mercedes motorhome.
"We are not yet fully committed to the program but it's something where the discussions are ongoing and we will very soon make our own decision".
"We completely acknowledge there is rivalry between the two of them, and that will intensify the longer the championship goes if it is between them", he added. With Mercedes looking comfortably quicker than Ferrari this weekend, Sunday's race looks set to be a fight for victory between the drivers of the silver cars.
"We damaged a new spec front wing so had to change to old spec", he said after pitting and returning to the track.