Spieth has three victories to his name this season, and won the Open back in July.
The American currently tops the FedEx Cup rankings.
After finishing runner-up in the first two legs of the FedEx Cup series, Spieth will be hoping to go one better at the BMW Championship which begins today.
Reflecting upon his season to date, Spieth claims incredible consistency will cement his place as the best golfer of all time.
“If I have the year I have this year the next 15 years, I’ll be the greatest player to ever play the game, if you judge it by major championships,” Spieth said.
Spieth has also revealed he feels hungry to stay top in the FedEx Cup rankings, adding: “I’m in a great position, looking to obviously stay in the No 1 spot.
“The FedEx Cup is a tremendous accomplishment, something I’m certainly striving for.”
Spieth will play the first two rounds of the BMW Championship with defending champion Dustin Johnson and PGA Championship winner Justin Thomas.
Johnson is third in the Fed ExCup rankings, while Thomas is second.
And Thomas is pleased with where his game is at the moment.
He said: “I’m not making the stupid mistakes the weeks I play well.
“I’ve been consistently driving it better this year.
“I’m always going to be in contention if I’m chipping and putting well.”