Bernie Ecclestone says he will be happy to see Audi come into Formula 1, but cautioned that the German manufacturer would - like Honda - struggle to catch up with Mercedes.
Audi/VW continues to be linked to either a future co-operation with Red Bull, or the more likely scenario of an eventual takeover of the Milton Keynes facility.
"It's good if any of these manufacturers come in, it will be super," Ecclestone told Motorsport.com.
"But it's difficult for them to come in with the rules that are already there, and a competitor of theirs that's already been for four or five years with an engine, and then they're going to come in.
"It will take them a couple or three years to catch up."
Asked if he thought Audi would finally make its mind up about F1, he added: "The problem is the engine situation. I believe Honda thought it wasn't a problem. I told them it would be..."
It has long been said that Audi has been sitting on the fence because Ferdinand Piech – recently ousted as chairman of the supervisory board of the Volkswagen Group – did not want to deal with Ecclestone.
However, Ecclestone insists that was not an issue.
"I don't have any problem, really. It's nothing to do with me," he said.