Romain Grosjean All Set to Leave Lotus For American-Owned F1 Team Haas

Frenchman Romain Grosjean appears close to leaving troubled Lotus for new American-owned team Haas after a frustrating Japan practice on Friday. (Daniil Kvyat tops free practice at Japanese GP)

With cash-strapped Lotus embarrassingly locked out of their hospitality unit in Suzuka for a second day over a payment issue, Grosjean stopped short of confirming speculation he was about to leave for a fresh challenge -- but only just. (Red Bull Disillusioned with F1)

"I've made up my mind," Grosjean told reporters after coming in 15th quickest in second free practice. "I can't comment any further yet but in my mind it's done. I'm happy with it.

"You will know soon," Grosjean added as Haas, who will use Ferrari engines, prepared to make a driver announcement next Tuesday at their headquarters in North Carolina.

"The more I think about it, I am more and more happy with it. It is not so easy to take a decision in your life, your career -- but it is part of our job."

Grosjean and Mexican Esteban Gutierrez, who drove for Sauber in 2013 and 2014 and is now the Ferrari reserve, are tipped to drive for Formula One's first American team since 1986.

Lotus's woes plumbed new depths on Thursday when they were locked out of paddock hospitality over unpaid bills as freight, including engines, was delayed.

Left to talk to media huddled under umbrellas in the rain, Grosjean put on a brave face but after Lotus officials completed scant mileage in Friday's rain-soaked practice to avoid potential damage, he threw off any pretence.

"I feel like I'm camping," he shrugged as equipment sat under tarpaulin outside the team's empty hospitality unit, in stark contrast to rival team suites which were full of buffets, fruit bowls and gleaming cappuccino makers. "I hate camping."

As protracted negotiations over a takeover by Renault drag on, Lotus lawyers are due in London's High Court next week in a lawsuit over unpaid taxes.

Their plight worsened last month when bailiffs arrived at the paddock at the Belgian Grand Prix to impound the team's equipment as their rivals were packing up to go home.

Amid so much uncertainty over the team's future and with Lotus mechanics facing more long nights in Japan to prepare their cars, Grosjean appeared to already have one foot out of the door.

"You can always change your mind but I am pretty pleased with my choice," he said, adding that his decision "should arrive sooner rather than later. In my mind, it is done. It is all done."