Bernie Ecclestone is set to return to Munich as his bribery trial resumes.
The F1 chief executive will be back in court on Friday, with the German news agency DPA reporting that prosecutors will call their first witnesses.
The report said the first witness will be former public prosecutor Hildegard Baumler-Hosl, whose dealings with Ecclestone relating to the Gerhard Gribkowsky corruption affair date back several years.
It is believed the prosecution will focus on whether Ecclestone's statements about the disputed $44 million in payments to Gribkowsky were consistent over the years.
The stakes are high. Many believe Ecclestone's position as chief executive is already untenable, but his reign will most certainly be over if he is convicted.
Christophe de Margerie, chief executive of the F1 fuel supplier and sponsor Total, warned: "Without Bernie, the system could collapse."
Also speaking to Challenges, a French language business magazine, Lotus team owner Gerard Lopez agrees that F1's 83-year-old supremo is "not simple to replace".
Quadruple world champion Alain Prost added: "I really don't know who could replace him. Maybe a duo comprised of one formula one expert and one financial."
At least publicly, Ecclestone remains confident.
Earlier, he flagged the likelihood of having to delegate some of his duties for the duration of the trial, but he now seems to be steering away from that.
"I know there is a lot of talk going on but I should be fine by the end of the trial," he told the Indian news agency PTI. "I am not sharing my work with anyone so far. Two days a week I am busy with the court work and the rest of it is enough for my F1 commitments."