The NFL pressured an Indiana man to give up his quest to trademark "Harbowl," even though the man might have had a legal right to do so.

Last February, Roy Fox said he spent more than $1,000 to file for the trademarks "Harbowl" and "Harbaugh Bowl," in anticipation that Jim Harbaugh's San Francisco 49ers and John Harbaugh's Baltimore Ravens might soon play in the big game.

"Right before the conference championship games last year, I thought to myself, 'Can you imagine if these guys played each other?'" Fox said. "If Pat Riley would go through the trouble of trademarking three-peat, why shouldn't I try this?"

But in August, a couple of weeks before this season started, the NFL sent a note to Fox saying that it was concerned that his recent trademarks could easily be confused with the NFL's trademark of Super Bowl.

"There were two questions asked of him," NFL spokesman Brian McCarthy said. "Was he affiliated with any NFL teams? The answer was no. And was he in any way affiliated with the Harbaugh brothers? And that answer was no."

In follow-up correspondence provided to ESPN.com by Fox, the NFL encouraged Fox to abandon the marks, citing conflict with its mark.

Fox said the league refused to provide him with any remedy. He first asked the league to reimburse him for his costs to file for the trademarks. He also asked for a couple of Colts season tickets and an autographed photo of league commissioner Roger Goodell.

He says the person within the league office he spoke to denied all his requests. After the language got increasingly more threatening, including one note that said the league would oppose his filing and seek to have him pay its legal bills, Fox eventually obliged.

In October, he sent the forms to the NFL, which were then sent to the U.S. Trademark and Patent Office. An online search shows that the trademarks were abandoned on Oct. 24, 2012.

Whether the NFL would have had the legal right to Fox's trademarks is highly questionable, according to R. Polk Wagner, a professor at the University of Pennsylvania Law School, who teaches intellectual property.

"My view is that the league was being overly aggressive in their interpretation that his marks were confusingly similar to 'Super Bowl,'" Wagner said.

Wagner said that if the league took Fox to court and tried to convince a jury that there was a connection based on confusion, it wouldn't have a strong case.

"It's important to point out that, even if the NFL didn't do what they did, they still wouldn't have his trademark by now," Wagner said, mentioning that securing a mark takes well more than a year.

Wagner says that doesn't mean that Fox still can't make T-shirts with his phrases, he just can't make money from others making them.

Mark McKenna, an intellectual law professor at Notre Dame, agrees with Wagner.

"While there's no question that in this case the trademarks are referring to, in some sense, the Super Bowl, saying that meets the legal standard would be a stretch."

McKenna said that the league has been known to be very aggressive in cases like these and that "nine of out 10 times, the person backs away."

The league and the Harbaughs have not trademarked anything related to the matchup. The NFL's McCarthy says the league hasn't yet decided whether any of its licensees will be able to make Harbaugh-related merchandise for the game.