Former Formula One world champion Jenson Button said he was off to do what he wants this year—but remained with McLaren. Part of that contract may force him to for Fernando Alonso, reports the . While there are other F1 drivers with experience at Monaco out of a drive this year, none are anywhere near as talented as Button.

At the time, McLaren referred to Button’s “break” as an “innovative three-driver strategy,” only two of its drivers would be doing most of the driving, and Button would be out of a drive. That is, unless full-time drivers Stoffel Vandoorne or Fernando Alonso can’t make it to a race.

In that case, 37-year-old one-time F1 world champion Button is still under contract with McLaren, and thus, still a viable option for the team. Per the BBC, Button’s contract obligates him to stand in for any driver who can’t make it to a race weekend.

Button is McLaren’s only serious option at this point, argues the BBC, as the tight, narrow circuit is one of the only chances for their butt-slow car to score any points. Alonso finished fifth there last year, when McLaren’s car also sucked.

McLaren won’t be taking any risks on a new driver when they have a known quantity on contract, ready to go. The car’s chassis is good, but its Honda engine is rumored to produce 100 bhp less than its top rivals—so they need someone that they know who can make that work.

McLaren could potentially get recently drive-less drivers Felipe Nasr or Esteban Gutiérrez back into F1 to drive Monaco, but those guys have nowhere near the experience that Button has there, so it’s a non-starter.

McLaren executive director Zak Brown told the BBC that Alonso’s stand-in was “not in place” just yet. Brown continued:

We have a few different options, we will state who that is when we know,.

Eric [Boullier], who runs the F1 team, is ultimately responsible for making the recommendation as to what driver should go in the car and I think he will be here at the weekend so I can save questions for him, he is working on it.

I wouldn’t want to share the conversations he has had with whom.

If Alonso decides IndyCar is a place he’d rather be or does something crazy like jump ship to Mercedes, McLaren also has the option to re-sign Button to drive in 2018 as well.

Admittedly, part of me would rather see an upcoming driver in McLaren’s get the opportunity at Monaco to get more seat time and prove their worth. But none of those guys may even want to fill in for Alonso when Alonso goes to race in the Indianapolis 500, as that car has a this season.

So, even if Button himself doesn’t want a go in F1's worst car, he’s probably their guy, regardless.