Stenson has won twice since the qualifying process for Gleneagles 2014 started, claiming the Deutsche Bank Championship and Tour Championship to also secure the 10million dollar bonus for winning the FedEx Cup.
That has left the 37-year-old Swede top of the World Points List with 136 points, just 36 less than the total with which Germany's Martin Kaymer - who ensured Europe retained the cup in last year's 'Miracle at Medinah' - secured his place on the 2012 team.
"Our points list is heavily weighted in favour of the world points list and Henrik has won twice in the FedEx Cup play-offs," McGinley said during a Q&A in Perth as part of celebrations marking one year to go to Gleneagles.
"He is 85 per cent there already and we are only in October. You can safely say that everyone in this room would have a bet that he can get that extra 15 per cent.
"At the start of the year the hot word on tour from the caddies was that Henrik was playing great, even though his performances were not quite showing that, and sure enough the caddies were proved to be right."
In contrast to Stenson's brilliant form, the likes of former world number ones Lee Westwood and Rory McIlroy, as well as Ryder Cup heroes Ian Poulter and Graeme McDowell, failed to qualify for the 30-man field in the Tour Championship last week.
Stenson's win at East Lake lifted him to fourth in the world rankings on Monday and dropped McIlroy down to sixth, but asked if he was worried about the form of his star names, McGinley added: "Not at this moment. If it was this time next year I would be worried.
"Last year the players were very dominant going into Medinah in their individual performances, we had a lot of success. This year we have a couple of guys who are flatlining but things can change so quickly in golf.
"There is a long way to go and I know I used to play better every second year when I knew Ryder Cup points were available."
Europe have won seven of the last nine Ryder Cups and American captain Tom Watson is desperate to regain the trophy and repeat his success at The Belfry in 1993 - the last time Europe lost on home soil.
Watson will be 65 at Gleneagles, which has led to fears that he will be out of touch with his players, but the five-time Open champion said: "I think some of the criticism of me is unfair, saying that I am old. That's just a fact.
"The other side of the coin is that I have been there before and the players know that I have been there before. It has not changed. In 1993 I said that I hoped I could bring some levity to it because the pressure is enormous; sometimes it's oppressive. You have to get that to subside in some way.
"Last year was great theatre even though we lost. We hope the theatre will be just as good next year but the outcome might be a little different."