Former Formula 1 champion Mario Andretti has advised Ferrari boss Mattia Binotto to consider moving the team into IndyCar.
In April, Binotto warned that a cost cap that was too low would force Ferrari to "look at other further options for deploying our racing DNA".
A $145million cap has been agreed for the 2021 season, but it is expected this will decrease further in the ensuing years.
As a result, 1978 F1 champion Andretti, who raced for the Scuderia in 1971 and '72, said Ferrari should consider a move to the U.S. series.
"Having Ferrari would be incredible," Andretti told La Gazzetta dello Sport. "Not only as an engine supplier but also as a chassis builder.
"It is clear that the rules should be changed, but I would like an all-Italian Dallara v Ferrari battle. The Cavallino [the Ferrari prancing horse] would increase interest in the championship, but there is an obstacle in the rules."
The obstacle referred to by Andretti is that at present Dallara is the sole supplier of chassis to IndyCar, while Honda and Chevrolet offer the only options for engines.
For Ferrari to consider an entry, changes would need to be made. Andretti added: "I suggest Binotto comes and proposes an idea to Roger Penske."
McLaren has recently made a return to racing in IndyCar by partnering with Schmidt Peterson Motorsports, combining to create Arrow McLaren Racing SP.
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