Looks like he turned them down:-
Lotterer has now told AUTOSPORT that he has decided to forgo the chance, which follows on from his F1 debut in a Caterham-Renault CT05 at the Belgian GP at Spa in August.
"I'm flattered because you don't get the call to do F1 every day," said the Audi World Endurance Championship driver.
"The one-off at Spa was a great thing for me to do, but to do more would have to have been in a better situation - I don't want to be a guy driving around at the back.
"If I could see opportunities in F1 to gain a better seat, it might be different, but it doesn't look like that."