"Sports marketers say the PGA's business model is fraying."

John Helyar and Burt Helm of Bloomberg look at the PGA Tour's sponsorship issues and lead with the suggestion that the WGC events are undermining smaller events more than actual purse size.

In recent years, the Tour created a tier of big-purse tournaments that allow top players to clear so much prize money that they skip the secondary events, said Ed Kiernan, who helps broker sports sponsorships for GMR Marketing in New York.

"I understand the Tour's fiduciary responsibility to the players," said Kiernan. "However, that simply doesn't justify the sponsorship expenditure for the lower-tiered tournaments."

The stratification started in 1999, when the Tour, in conjunction with pro circuits abroad, began the World Golf Championships, four tournaments featuring top players from around the world and now paying $8.5 million in prize money. In 2007, the PGA created a series of four $7.5-million-purse tournaments called the FedEx Cup, which pays a $10 million bonus to the player with the best cumulative performance. Elite golfers gravitate to the "A" tier events.

The "B" tier tournaments, with $5 million to $6 million purses, and the "C" tier events, with purses below $5 million, are left to vie for players with sufficient name recognition to attract viewers and sponsors.

Verizon ended its sponsorship of the "B" tier Verizon Heritage because it wasn't drawing enough viewers overseas, said Rebecca Carr, vice president, global enterprise marketing, at Verizon Business, which seeks to tap corporate growth markets abroad.