McLaren have parted company with the man who was employed to run their Indycar programme.
The departure of Bob Fernley comes less than 24 hours after Fernando Alonso failed to qualify for the Indianapolis 500.
Alonso was driving a car run by McLaren, who set up a new team with Fernley at the helm specifically for this year's event.
The team are now considering a future in Indycar alongside Formula 1.
A spokesman confirmed Fernley "was no longer with McLaren". He added that Fernley's contract ran up to the race, which is on Sunday.
Fernley, a former Force India deputy team principal, joined McLaren in November, shortly after the team confirmed they would attempt to win the Indy 500.
Alonso, who has set himself the target of winning the Indy 500 to complete motorsport's triple crown, acknowledged that the team had struggled from the outset.
"We were not fast," the two-time Formula 1 champion said, "not only today; the whole event, we were struggling a little bit."
Only Graham Hill has won the triple crown, which most consider to be the Monaco Grand Prix, Le Mans 24 Hours and the Indy 500.
McLaren's Indycar preparations were in trouble from the start.
The team planned only one test before starting running at Indianapolis, but that day at the Texas Speedway in mid-April was beset by problems that limited running.
At the official Indianapolis test day at the end of April, the McLaren barely ran as a result of electronic problems.
And the team had difficulties throughout the practice days last week.
The car struggled to run on the first day of practice because of electrical problems. Alonso crashed after less than 50 laps of the second day. McLaren planned to go out early on the third day but had problems building up a new car and they failed to run at all.
That left only one day of practice for Alonso and McLaren to prepare for qualifying at the weekend, which proved too big a task.
Alonso made five four-lap runs on Saturday but just missed out on a guaranteed place on the grid given to the fastest 30 cars. He then finished fourth of six drivers on 'bump day' on Sunday, when the final three grid positions are decided.
Alonso said: "These four laps in qualifying especially are four laps where you are flat [on the throttle]. There is not really anything big that you need to drive. As long as you don't lift, it's more or less the speed of the car that puts you in one position or another - or the time of the day.
"We had multiple attempts [on Saturday] and at different times. We should be OK if the car was quick enough, but we didn't manage to achieve that."
For Sunday, McLaren sought help from the leading Andretti and Penske teams to set up the car, to no avail.
Alonso said: "We went out with an experiment that we did overnight. We changed everything on the car because we thought that maybe we need something different to go into the race with some confidence. Because even if we were qualifying, we were not maybe in the right philosophy to race next Sunday. We went out not knowing what the car will do in Turn One, but we're still flat. So we tried."
McLaren sporting director Gil de Ferran, a former Indy 500 winner and two-time series champion, said it was "the most painful day" in his career.
The Brazilian was sent over to America to try to rescue McLaren's Indy campaign after it became clear to the company last month that it was not on the right track.
De Ferran said: "We took on a huge challenge. We were racing against some very experienced teams in Indy car and unfortunately we came up a little short, try as we might.
"It is very painful. We had a lot of support from the fans, from our partners, from frankly the whole lndycar community that welcomed us with open arms and helped us navigate through some uncharted waters for a lot of us.
"I want to also think Fernando for his tremendous effort. We couldn't have asked any more from him. He drove like the champion he truly is; we just didn't give him a car that was fast enough."
McLaren chief executive officer Zak Brown said on Monday that there had been discussions about potentially buying Alonso a seat in the race, replacing a driver in a car that had already qualified.
But this was ruled out because Alonso "didn't feel right to take another driver out that has earned it because his team has bought the seat".