Detailed negotiations with Perth club owner, Geoff Brown, are progressing well – so much so that the Scottish Football Association has now been notified about the potential for foreign investment at McDiarmid Park.
An agreement over a sale could even be reached before the end of the season.
The US investor, who has a legal background, was a guest of Saints earlier this month and, along with an associate, attended the Premiership matches against Ross County and Hearts during a week-long stay in Scotland.
Having been involved in talks for several months before then, he liked what he saw and discussions have advanced significantly since the trip.
The number of parties interested in a takeover has run into double figures but no others have got anywhere near to this stage.
Brown has previously admitted that the vast amount of prime site land at McDiarmid has proved to be problematic in terms of finding a suitable buyer.
For any deal to get completed, legal guarantees would be put in place on that front.
Saints will also be provided with proof of funding that underpins the bid and the future running of the club.
It is understood the prospective buyer assessed the landscape in leagues across England and Europe before setting his sights on St Johnstone.
A deal being completed over the next few months is looking increasingly possible, meaning Saints could be foreign-owned for the first time in their 140-year history.