So she will return home to Cambridge Stud and be a million-dollar mum, the winner of her last race at Caulfield just days ago.
What lies ahead for Probabeel, in terms of suitors either here or in Australia, is a decision for another day. But whenever truly great horses retire the mind can't help but catalogue the moments that set them apart from the normal equines.
For Richards and Bosson it was that magical 300m at the end of the Surround Stakes at Randwick on February 29, 2020, a performance so rare it belonged on a day that only comes around once every four years.
"That was special what she did that day," says Richards.
"When you look where she is at the 300m mark, second last, to come and beat Australia's best fillies on their home ground, stuff like that is almost impossible to do."
Bosson was along for the ride and it wasn't the most comfortable, with one of the gifts that helped make Probabeel great also constantly getting her into trouble.
"She was so laid-back and took nothing out of herself, which really helped her before and after races," says Bosson.
"But it was really frustrating during races because she always hit that flat spot on the home bend and made it hard on herself.
"Really, I can't believe what she did that day."
Probabeel was beaten only once (on debut) in six starts in New Zealand but it was in Australia where she painted her masterpieces.
"She was simply too good to race over here all the time, if she had of she might have been unbeaten for a few years. She might have won 20 Group1s," says Bosson.
In Australia, she won an elite Sydney mile race in the Epsom but it was her Melbourne form that sealed her place among the greats, beating the likes of Arcadia Queen and Zaaki when they were supposed to be unbeatable.
"Racing at that level is so, so hard and to beat those horses, and plenty of others, it makes us all very proud," says Richards.
Had it not been for the cruelty of the weather gods Probabeel's record would be more remarkable. Her 18 starts on good tracks brought 13 wins and three placings whereas her 11 starts on the wet tracks were winless.
For the Lindsays, who bought Probabeel after she had been knocked down to David Ellis at Karaka for $380,000, Probabeel is the embodiment of why they have poured so much into revitalising Cambridge Stud.
And now their castle has a queen.
SIX OF THE BEST
Probabeel's greatest hits as told by trainer Jamie Richards:
1. Surround Stakes, Randwick, Feb 2020: "Horses shouldn't be able to do what she did that day."
2. Futurity Stakes, Caulfield, Feb 2021: "Came from a wide barrier and beat a star in Arcadia Queen in a Group 1."
3. Epsom Handicap, Randwick, Oct 2020: "It is a good horse's race and I took a few hints out of the Chris Waller playbook to get her spot-on for that [big race in Sydney]."
4. Might And Power Stakes, Flemington, October, 2021: "Those elite w-f-a Group 1s at the spring carnival are very hard to win, especially beating a horse like Zaaki."
5. Karaka Million, Ellerslie, Jan 2019: "She overcame barrier 14 and was stunning. That was the day she really arrived."
6. Karaka Classic Mile, Ellerslie, Jan 2020: "A massive win, just overpowered them in a 1:33 mile."