Bernie Ecclestone says he would have done whatever he could to stop Fernando Alonso skipping the Monaco Grand Prix in order to race at the 2017 Indy 500 if he was still in control of Formula One.
But the Indy 500 may have looked even more tempting given McLaren are now last in the Formula One constructors' world championship after two races without a point.
Button, however, won the Monaco Grand Prix, the most glamorous race in Formula One in 2009 - the same year he took the world title with the now defunct Brawn team.
Jenson Button will stand in for Fernando Alonso in the Formula 1 Monaco Grand Prix, with McLaren racing director Eric Boullier saying that it was a "very straightforward" decision.
"I'll drive the MCL32 around Monaco in the McLaren sim beforehand, and I reckon I'll be ready for the race after doing that".
The McLaren chassis is quite strong, but the vehicle is being let down by its Honda engine, which is said to be at least 100bhp down on the best in F1.
Button's compatriot and former team-mate, Mercedes driver Lewis Hamilton, said: "I hope Jenson comes back and it will be great for the sport if Jenson comes in".More news: BP workers discover "uncontrolled gas release" at North Slope well house
Alonso's Belgian rookie team mate Stoffel Vandoorne joked that he had chose to enter the Spa 24 Hours sportscar race on home soil instead of the Hungarian Grand Prix.
Having signed a two year ambassadorial contract, Button is officially the reserve driver for the team but he effectively went into semi-retirement at the end of last season.
Alonso was forced to retire from the Australian and Chinese Grand Prix after his McLaren auto continued to give him problems.
A press conference is planned for Friday in Bahrain, though a McLaren spokesman said he was not in the Kingdom. The Indianapolis 500 will be the only 2017 IndyCar race in which Fernando will compete, however, and the Monaco Grand Prix will therefore be the only 2017 Formula 1 race in which he will not compete. It's also my responsibility to cover any ifs - if he was committed to something, if he was sick - anything that would have stopped him from driving in Monaco.
"Or I can win different races in different series in moments in my career and be a driver that can race and win in any auto in any series".
"I like Jenson and he is still one of the best drivers, and his calibre and experience is way ahead of the other drivers able to take that spot, for sure". "I think it's great that McLaren and Zak joined forces previous year".