The 32-year-old is is the form of his life, having finally made a breakthrough in the majors by winning the US Open earlier this year.
Leading at the halfway stage in Atlanta, he is also on course to add the Tour Championship and, with it, the FedEx Cup.
“Absolutely,” replied Harmon when asked if Johnson was ready to embrace the responsibility of being Team USA’s top-ranked player in a team environment at Hazeltine.
“Right now Dustin Johnson is the best player in the world. I told him after his last win (in the BMW Championship) a few weeks ago that he is starting to remind me of Tiger Woods back in the old days.
“He drives it further than anyone since we convinced him to go with a little fade off the tee. He hits more fairways than ever hit and he’s improved both his wedge play and his putting tremendously.
“He’s at the point now where, when he’s on his game, he is very hard to beat. DJ is one of those unique athletes who plays with no fear. He is not afraid of anything, anybody or any shot.
“I think that positivity can carry itself into a team event like this. You can pretty much pair him with anybody.
“Heck, if a guy got injured, he’d probably tell the captain, ‘I’ll go and play the two opponents myself’ as that’s the type of guy he is.
“Dustin is the one you would look at to have the best chance of being the leader for Team USA next week.”
* Sky Sports is the only place to watch The Ryder Cup live, as part of an autumn of sport including Premier League, F1, England cricket and rugby Autumn internationals