An investigation into the New England Patriots' AFC Championship victory in January concluded that Patriots personnel probably meant to modify game balls, some of which were inflated less than the league allows. A report released Wednesday said Brady was probably aware of the practices in what became known as "Deflategate."
Many former players have said the Patriots could have gained a competitive advantage, as slightly deflated balls are easier to throw and catch.
Read MoreNFL report: Tom Brady knew about deflated balls
Patriots owner Robert Kraft, who was not implicated in the report, criticized its findings Wednesday, while Brady's agent, Don Yee, called it a "disappointment."
Brady took in about $19 million from his work on the field last year, according to sports contract website Spotrac. He made an additional $7 million from sponsors in 2014, according to a Forbes estimate.
Those sponsorship dollars likely will not dry up, because sports fans have a "short-term memory," Marshall said.
Read MoreCan anything hurt the NFL?
Enough time has passed since the "Deflategate" game that anti-Brady sentiment has calmed, said Manish Tripathi, an Emory University marketing professor and co-founder of Emory Sports Marketing Analytics.
"I don't see this having a big impact on his sponsorship dollars," he said.
But the report could wreak havoc on jersey sales. Brady's jersey sold fifth-best among all players from April to October last year, according to NFL Shop. Those sales could suffer, at least in the near term, Marshall said.
—CNBC's Dominic Chu & Jessica Golden contributed to this article.