The NFL has not banned the use of non-Bose headphones, but players will continue to be subject to fines if they do not cover up competitors' logos under certain guidelines.
Kaepernick has been wearing headphones at his postgame press conferences since he arrived in the league, but he had been covering up the lowercase "b" logo for Beats by Dre since he was warned last year. This past week, Kaepernick, who is a paid endorser of the brand, did not do so.
Although players cannot wear unapproved logos up until 90 minutes after the game, the NFL's attention on headphones became heightened after it signed Bose to a coaches headset deal earlier this year.
Motorola, which had the deal to outfit the coach headsets through 2012, did not make headphones for the mass market so there wasn't an issue.
Sources say the league will allow any player to wear headphones during media interviews if the logo of that brand is covered up. The league also will allow players to wear headphones with competing logos off the bus, into the stadium and on the field for warmups before they get into uniform.
Since most of the shots of players in their headphones come way before the game, that allows companies like Beats and Monster, which sponsors Marshawn Lynch, to still get some value.
While some have speculated that Apple, which bought Beats by Dre for $3 billion in August, would simply pay fines incurred by players, the reality is that fines can escalate per violation and players could even be suspended.
Kaepernick would not disclose Thursday if Apple would pay the fine, but a source close to Kaepernick said the company did not.
Sponsorship evaluation firm Front Row Analytics said that media coverage of Kaepernick's postgame was worth more than $350,000 in equivalent advertising for Beats.
The penalty for on-field commercial logo violations are not specified in the league's collective bargaining agreement. The CBA does say that the league can impose a fine and even suspend a player depending on the "severity of the violation."
The NFL's new headphone rules are actually a compromise in that the league is still allowing players to wear non-Bose headphones during pregame warmups.
As the category has gotten more competitive, headphone brands have turned to athletes.
Richard Sherman and Kaepernick became the most high-profile Beats By Dre endorsers outside of LeBron James, who received an equity stake and cashed in to the tune of more than $30 million when the company was sold.
Monster signed Lynch in January a few weeks before the Seahawks won the Super Bowl.
Bose, to support its NFL deal, signed Seahawks quarterback Russell Wilson, Green Bay Packers linebacker Clay Matthews, Arizona Cardinals wide receiver Larry Fitzgerald, Atlanta Falcons quarterback Matt Ryan and New England Patriots cornerback Darrelle Revis.
Logo violations in the recent past also have come with a $10,000 fine.
Washington Redskins quarterback Robert Griffin III was fined on two separate occasions for wearing the logo of his sponsor adidas, which no longer has a deal with the league. Carolina Panthers quarterback Cam Newton also was fined $10,000 for having Under Armour clips on his helmet visor last season, as the logo is permitted on field on players' gloves and cleats only.