Haas is edging ever nearer to announcing its full 2019 driver lineup.
Kevin Magnussen, who is almost certainly staying, admitted at Sochi that the delay is frustrating.
"It's a little frustrating to wait," he admitted, "but the team wants to announce both drivers at the same time.
"But from my side there is no panic."
Team boss Gunther Steiner admitted that the time is finally nearing.
"I promised last week that we would announce our drivers within 14 days, so that's either here or Suzuka," he said at Sochi.
It is believed that Romain Grosjean is the favourite for the second seat, after recovering his form following an early season slump.
"As Romain says himself, it seems that he has found the key that he lost," said Steiner.
"He's been with us from the very beginning, risking his career because he did not know us. Whatever happens, I think our personal relationship will not be affected," he added.
If there are other contenders for the second seat, they may be Mercedes juniors Esteban Ocon and George Russell.
Steiner insisted that, despite Haas's Ferrari links, the American team is free to choose its own drivers.
"Of course we consider their (Mercedes') candidates, because they are both good drivers," he said. "But we think first about our interests. If Mercedes has too many drivers, why is this someone else's problem?"
