He is great in such phone conversations because, like his time behind the racing wheel, he is never on cruise control.
"This is a good little break for me before the race," he says. "I get a chance to see some family, see my dogs. A little break, then I'll be ready."
Ready, indeed, for the "greatest spectacle in racing." If you are a longtime Indianapolis 500 fan, you can almost hear Sid Collins intoning those words.
Memorial Day weekend and the Indy 500 are peanut butter and jelly, ketchup and French fries. They were meant for each other.
So are Indy and the name Andretti.
Marco is just 27 years old, has magazine-cover good looks and can make a race car go faster than a speeding bullet. In one practice session earlier this month, he turned a lap of 232.239 mph, the fastest lap since Scott Dixon did 233-plus in 2003.
When they call for gentlemen to start their engines Sunday, Marco will be on the outside of the second row. He agrees that is a nice place from which to stalk the leaders.
Ed Carpenter qualified fastest at 231.067. Andretti was sixth at 230.554. The difference is about how long it takes to sneeze. Former winner Buddy Lazier (1996) qualified last, or 33rd, at 227.920. That means there is a difference of three seconds and an eye blink from front to back of the pack.
That's the fastest starting field ever for this race, raising questions of safety. Not for Marco Andretti.
"That's just cool," he says.
Andretti is much more than a legacy driver. His grandfather is the famed Mario Andretti, who won so many races in so many different kinds of cars that, where others need a trophy case, Mario needs a trophy barn. He is the only person to win the Indy 500 (1969), the Daytona 500 (1967) and a Formula One world title (1978).
He is 74 and so far away from a rocking chair on the front porch that grandson Marco laughs at the thought.
"I was out early the other day for practice and he was taking people out for runs in the two-seater," Marco says. "When it was time to leave and almost getting dark, he was still running people out there."
One of the people Mario took for a ride last week was a 102-year-old woman, who complained when she got out of the car that he was allowed to go only 180. She wanted to go 200.
"When Kurt Busch [another Andretti Autosports driver] got into the wall," Marco says, "and there was a few minutes where we weren't sure he could go, my grandpa walked in and said, 'I'm ready.'"
The person who would "put grandpa in" would be grandpa's son and Marco's dad, Michael Andretti. He owns and runs the race team, is a multimillionaire through real estate investments of funds from his own highly successful racing career and has also become somewhat of an amateur psychologist when it comes to his son, Marco.
Marco never wanted to be anything but a race driver, even though he was a pretty good youth basketball player.
"I had that height problem," he says.
But at age 10, already running successfully on a national level in go-karts, he quit.
"For a while, it was just win races and go home," Marco says. "It wasn't fun. Even at that age, all the cameras were on me, for obvious reasons. I just decided it wasn't fun. So I quit. My dad and grandpa encouraged that. It was their reverse psychology. They knew I'd miss it."
For years, the voice on the radio to Marco during races was Michael's. Marco says they would go at it verbally, and that was no problem for them.
"We weren't arguing," Marco says. "We're just passionate."
But the "passionate" exchanges sometimes distracted the team as a whole, so Michael found the opposite of himself to be Marco's radio lifeline.
"Kyle Moyer [team director of racing operations] is my chief," Marco says. "Talk about a calm guy. The other day in practice, a fuel line broke. I was in the pits, luckily, and the engine started burning. I didn't see that.
"Kyle says, 'Why don't you get out of the car, pal.'
"I was in no hurry. I kind of said why. He looked at me again and says, "Dude, get out of the car. It's on fire."
For the Andrettis, the Indy 500 is the ultimate test. Mario ran it 29 times, won once, was in the top 10 11 times and second once. Michael ran 16 times, never won and was in the top 10 nine times.
In 2006, the 19-year-old Marco led by a full second crossing the finish line for the last lap. With just yards to go, Sam Hornish Jr., sling-shotted around Marco and won by 0.0635 of a second. This will be Marco's eighth start and he has four top-five finishes.
If the weekend goes the way the Andrettis want, that Indy curse will be over.
On Saturday, Mario will be the honoree on Legends Day. On race day, Michael will direct the team strategy. Grandpa will be pacing and grandma Dee Ann will be nearby, puffing on one of her little cigars and hoping for her family's ghosts to be exorcised.
"We've been in such good position so many times," Marco says.
"You know, when it happens, it will probably be on one of those days I'm 16th on the last pit stop."