As more sponsors speak out against NFL, pressure mounts for Goodell to resign

(CNN) – Sponsor after sponsor has come forward, speaking out against the NFL: McDonald's, Verizon, PepsiCo, and Anheuser-Busch.

Procter & Gamble pulled out an NFL breast cancer campaign Friday.

"Domestic violence is completely unacceptable and we have strongly urged the NFL to take swift and decisive action to address this issue, and we will determine future actions as needed," the company said in a statement.

"The pressure will be mounting" for NFL Commissioner Goodell to resign, said Gene Grabowski, a senior strategist at public relations firm LEVICK.

"Right now, the sponsors and advertisers are voicing their concern and distancing themselves from the NFL. But they are in the main keeping their contracts in place," he said.

"If they start to back out of those contracts, the pressure is going to be enormous on Mr. Goodell," said Grabowski.