Mendenhall's lawyers filed suit Monday in U.S. District Court in North Carolina, seeking roughly $1 million in damages from Hanesbrands, Inc., the Winston-Salem-based corporate parent of Champion.
The complaint says Champion's decision to end its endorsement deal with Mendenhall in May, days after he questioned the public celebration of bin Laden's death, violates a contract extension the two parties signed in 2010, worth more than $1 million. Mendenhall first signed a deal to endorse Champion products when he entered the league in 2008.
"For Rashard, this really is not about the money. This is about whether he can express his opinion," said Steven Thompson, a Chicago-based attorney representing Mendenhall.
A spokesman for Hanesbrands did not return a call seeking comment by early Tuesday afternoon. But legal experts said Mendenhall might have a difficult time proving his case.
"An athlete contracts away his free speech rights in signing his endorsement deal," said Jeffrey Standen, a sports law professor and associate dean at Willamette University College of Law in Salem, Ore. "What the sponsor is buying is the athlete's name and image, and their name and image are related to public behavior and opinions."
Shortly after bin Laden was killed by a team of Navy SEALs, Mendenhall tweeted, in response to scenes of euphoria around the U.S., "What kind of person celebrates death? It's amazing how people can HATE a man they have never even heard speak. We've only heard one side..." He also tweeted on the Sept. 11 attacks: "We'll never know what really happened. I just have a hard time believing a plane could take a skyscraper down demolition style."
The comments prompted significant anger, leading to a clarification by Mendenhall and a separate statement by Steelers team president Art Rooney II distancing the organization from Mendenhall's remarks. But his number of Twitter followers nearly doubled to around 37,000 within a few days of the tweets.
Hanesbrands' decision to drop the Steelers star was likely a "kneejerk reaction" made within 48 hours of the tweets, Thompson said. The swiftness of that move contrasts with Champion's silence regarding other contentious tweets by Mendenhall, the lawsuit claims.
"Anyone with knowledge of the slave trade and the NFL could say that these two parallel each other," Mendenhall wrote.
About six weeks later, he tweeted that women who decline to perform oral sex on a partner should be aware that "It's either gonna be you, OR some other chick."
"Hanesbrands at no time prior to May 2011 suggested that it disagreed with Mr. Mendenhall's comments or that his tweets were in any way inconsistent with the values of the Champion brand," the lawsuit says.
That might not matter, according to Michael McCann, director of the Sports Law Institute at the Vermont Law School.
"The company's concern, I would imagine, is not really the content of what he's saying, but the public reaction to what he's saying," McCann said.
Most athlete endorsers have contracts that include deliberately vague language concerning off-the-field behavior that companies can use in situations exactly like these, McCann said. Such language was cited in a May 11 letter to Mendenhall's representatives, written by Lynette Fuller-Andrews, a lawyer for Hanesbrands.
The running back's contract included provisions barring Mendenhall from actions that would bring him "into public disrepute, contempt, scandal or ridicule, or tending to shock, insult, or offend the majority of the consuming public," along with other terms, Fuller-Andrews wrote.
"It's going to be tough for him to prevail, because that gives the company a lot of leeway," McCann said. "Once you sign off on very generic, all-inclusive phraseology, it's very hard to get out of that."
"Morals clauses" are commonly invoked when an athlete's behavior makes the wrong kind of headlines. Philadelphia Eagles quarterback Michael Vick lost endorsement deals after revelations about his participation in a dogfighting ring, and Tiger Woods was dropped by some of his sponsors following the disintegration of his marriage over accusations of serial infidelity.
But the ease with which athletes can land in trouble with social media tools such as Twitter likely mean endorsement deals in the future will be different, said Porcher Taylor, a professor in the School of Continuing Studies at the University of Richmond.
"Every celebrity endorsement contract of any kind in the future must have a Twitter/Social Media clause," Taylor wrote in an email. "I will be so bold as to state that the failure to not have such a clause would be tantamount to endorsement contract drafting malpractice."
Copyright 2011 by The Associated Press