Spain - Frederic Vasseur has admitted that the departure from Sauber of technical boss Jorg Zander was "awkward".
The Swiss team announced suddenly at the end of last week that just 18 months after re-joining Sauber and Formula One, Zander has left.
'Incidents involved alcohol'
Blick newspaper reports that the departure comes after several personal incidents involving the German, who worked in F1 for BMW, Williams, Honda and Brawn.
It is believed the incidents involved alcohol.
"We had to part in a rather awkward situation," team boss Vasseur said.
"But now we have to look forward, as we are already starting to develop the car for 2019. We must also prepare for the race in Barcelona, so let's see how we perform there," he added.