In 2007 offensive coordinator Trestman and the other coaches at North Carolina State were fired. He had time left on his contract but didn't have a job. Payton invited him to Metairie, La., to be a "voluntary" assistant for the Saints.
Trestman attended meetings, watched tape, went to practices and then wrote observations for Payton. Maybe three pages a day.
"It was a great help to have another set of eyes from someone who had been in this system long before I ever cut my teeth in it," Payton said.
Every year at the scouting combine, Payton and Trestman will grab a coffee and watch the quarterbacks work out from a remote section of Lucas Oil Field in Indianapolis. They will evaluate the players and compare notes.
So Payton has a pretty good handle on Trestman. That's why he has called Bears general manager Phil Emery repeatedly in recent days.
"I've recommended I think three people in seven years, and he was one of them," Payton said.
For whatever reasons, Trestman's past chance to become an NFL head coach came and went. So he took a northerly detour.
In Montreal, the creative young coach with so much promise became a seasoned 57-year-old who had realized his dreams by taking one calculated risk after another.
You could see the special in Trestman long ago.
He and I talked a lot about quarterback play that day in Tempe.
"A quarterback can't be great on his God-given skills alone," he said. "No quarterback ever has done it."
The grease board awaits.