No gain in GP2, Mario tells Marco

"I think right now it's a bit premature," the 1978 champion and winner of 12 Grands Prix told Reuters by telephone on Saturday.

"All the experts say he needs to go to GP2. I say no. GP2 would be a sideways move, there's nothing to be gained."

Nineteen-year-old Marco, son of former Grand Prix racer Michael Andretti, is on the Formula One radar after finishing runner-up by the closest margin ever in this year's Indianapolis 500.

Triple champion Jackie Stewart, who raced against Mario Andretti in the early 1970s, said this week that Marco could be just what Formula One needed to get Americans seriously interested in a sport struggling to raise its profile in the United States.

The Scot suggested that Marco should "have the courage" to move to Europe and learn the Formula One circuits in order to be in the frame for a race drive in 2008.

Former CART champion and IRL team owner Michael Andretti, the last American driver in Formula One until Red Bull's Scott Speed came along this year, spent an unhappy season with McLaren in 1993.

He left after 13 races that produced just one podium.

Michael said he would not let that colour his judgement when it came to his son's career but it would have to be a pretty good deal that lured him away.

"Kim (Green, co-owner of the Andretti Green IRL team), Kevin (Savoie) and I wouldn't stand in his way...but it has to be the right deal. I'm for what's best for Marco," the 43-year-old told Reuters from Kansas City.

By that he meant a season as a test driver for a top team such as Ferrari rather than GP2.

"It would be shame on us if we made the same mistakes again," said Michael.

Not that there were any real decisions to be made just yet: "Let's get some offers before we think about it," he added.