The 50-year-old, who won the US Senior Open last month, heads a strong field for the season’s final over-50s major, which is being held at the Perthshire venue for the first time.
Harrington, who still plays a lot of his goal on the main tours, has been crunching drives on the practice range this week and also out on the course.
New tees have been added at the sixth, 12th and 18th specifically for this event, but the one at the last isn’t stopping Harrington from getting over the saddle on the fairway.
“I don't even need a carry on it, no,” he said of the 555-yard closing hole. “It's downwind, downhill. I had 75 yards in on Monday, when it got all the way down the second one (saddle). Today I must have had 150 front today off a good drive.
“But that's only one hole. There's only two holes that I would say hitting a driver out there is advantageous. And, remember, the further you hit it, it's harder to hit it straight, too.”
Harrington heads a field that also includes fellow major champions Ernie Els, Darren Clarke, Retief Goosen, Paul Lawrie and Jose Maria Olazabal.
“I’m looking forward to,” he added. “This is my first year out here and, after three second places, it was nice to get a win in the US Senior Open.
“Some of the courses really suit me whereas other weeks, including this one, it’s a tougher task to get a win. I wouldn’t be jumping out saying this is a course made in heaven for me. But this is a good golf course.”