The most recent public opinion poll showed that 52 per cent of local citizens were against the bid, with only 36 per cent in favour.
Last month USOC officials were forced to deny a report in the respected Wall Street Journal that they would pull the bid if support for Boston 2024 did not improve soon.
But the bid will almost not be able to continue if it does not receive the majority of support in a local referendum planned for November 2016.
"We are very confident that Boston is going to get on a much more positive track," Probst, attending the Pan American Sports Organization Extraordinary General Assembly here, told insidethegames.
"We are fully supportive of their Organising Committee and we are looking forward to working with them in the future.
"We obviously want to partner with them as best we possibly can and provide every bit of support we can to their effort."
It was significant that John Fish, the chairman of Boston 2024, travelled to this General Assembly and took the opportunity to meet several International Olympic Committee members who were in attendance.
He has now returned to Boston to continue to try to get the public behind the bid.
A series of public meetings are currently scheduled where the public have the opportunity to find out more about the plans of Boston 2024.
The first one, held last month, lasted for four hours.
Boston 2024 to hold referendum on Olympic bid
March 2015: Support for Boston 2024 continues to decline, new poll reveals
March 2015: Boston 2024 needs to convince citizens this is a "fiscally responsible bid", says USOC chief executive
March 2015: Anger after former Massachusetts Governor given top role by Boston 2024