What would force a Heisman Trophy winner, especially one from Notre Dame, to sell their award? It's one of the most exclusive clubs in sports to belong to, yet I'm perplexed on why anyone would want to sell it.

I remember listening to a radio inerview with Jim McMahon, and he was asked if he ever wears his Packers Super Bowl ring. He said, "no, it's in the drawer with the other one", meaning his Bears ring.

He said the rings didn't mean anything to him. "I was there, we won the Super Bowl. That's enough for me."

Incidentally, Paul Hornung also sold his Heisman many years ago.

If someone wants to pay you $XX for an item and that is more than you would be willing to pay to keep the item, the financial decision is pretty easy to make. Turning down the sale, in effect, equals making a purchase.

After that it is just about the sentimental or emotional value which, as you have noted, doesn't mean that much to everybody.

From the article:

"Beginning in 1999, winners of the Heisman Trophy have been barred from selling their trophies by the trust that oversees the honor."

and

"Last month, it was reported that Brown’s 1987 Heisman Trophy, which he sold to a private collector a year ago, would be going up for auction."

from selling their trophy.

I think you are supposed to read the sentence in question to mean that awardees from 1999 forward have been barred from selling their trophies by the trust that oversees the honor.

All the sales listed are by people who won it before 2000.

I'd imagine they rewrote the bylaws of the award to prevent any winner from selling as part of their ownership transfer. Prior to 2000 they probably never considered it and simply handed it over as you would any other gift/award.