Haas team principal Gunther Steiner believes the US squad could 'mess something up' on its Formula 1 debut in the Australian Grand Prix because of the disruptions to its preparation.
Following a problematic second pre-season test littered with reliability issues, Haas's hopes of making up ground during free practice were compromised by a rain-hit day, with Romain Grosjean and Esteban Gutierrez completing 32 laps between them.
Steiner says the chance of something going wrong this weekend is higher than he would like.
"We can handle it, but it's not like we are going in prepared saying we have hit every milestone here," he said.
"There is always [the chance] we could mess something up, and I wouldn't blame anyone if we did.
"We've just not had the time or the possibility to train for it. It takes a bit of time, and days like today don't help."
"We are not as prepared as we could be. We need to make progress.
"We need to show how good the car can be and we just need to do more running.
"We tried one race simulation in Barcelona and a qualifying simulation today, but we couldn't do it because you never knew [with the weather]."
With further rain forecast on Saturday, Haas is set to play it safe in FP3 to avoid compromising qualifying, and ultimately the race.
"The team doesn't want to take risks because if you start to do that what you learn is a very small amount, so there is no point," said Steiner.
"The opportunity [to learn] is not big enough, so we will just try to make sure the car is ready for qualifying and be done with it.
"If we damage the car or do something stupid, and you cannot immediately go out in Q1, you are done.
"So we will take fewer risks tomorrow than we have today - if the weather conditions are similar, obviously."