Mark O'Mara told reporters he met with his client and, after discussing the situation, decided to seek to have Circuit Judge Jessica Recksiedler recuse herself because her husband's law partner has been hired by CNN as an analyst on the case. Chief Judge Alan Dickey confirmed the filing Monday afternoon, the Orlando Sentinel reported.
"What I don't want to happen is to wait a month or two, then find out what we thought was a potential conflict is an actual conflict," O'Mara told reporters Monday.
The newspaper said Recksiedler is almost certain to grant the defense motion since Florida law requires only that a person show a reasonable belief the judge might not be fair.
It wasn't known which judge would be assigned to replace Recksiedler.
Zimmerman, 28, is charged with second-degree murder in the Feb. 26 shooting death of Trayvon Martin, 17. Zimmerman, a community watch volunteer of white and Hispanic heritage, says he was acting in self-defense when he shot Martin as the unarmed black teen walked through a gated community in Sanford.
Meanwhile, a Florida firefighter is being investigated after criticizing the prosecutor in the Zimmerman case on Facebook, officials said.
Miami-Dade Fire Department Capt. Brian Beckmann posted his thoughts on Facebook after special prosecutor Angela Corey announced the charges against Zimmerman Wednesday, The Miami Herald reported.
"Listening to Prosecutor Corey blow herself and her staff for five minutes before pre-passing judgment on George Zimmerman," the post read.
"The state seeks reelection again, truth aside. I and my coworkers could rewrite the book on whether our urban youths are victims of racist profiling or products of their failed, [expletive], ignorant, pathetic, welfare dependent excuses for parents, but like Mrs. Corey, we speak only the truth," Beckmann continued. "They're just misunderstood little church going angels and the ghetto hoodie look doesn't have anything to do with why people wonder if they're about to get jacked by a thug."
Beckmann's post was published Friday by theGrio.com, a Web site geared toward African-American issues.
In response to the publication, Miami-Dade Fire Rescue told theGrio.com it was investigating the captain's post.
Beckmann defended his posting, saying in an e-mail to the Web site: "I am a private citizen and have the same right to freely express an opinion on any subject that anyone else does. I choose not to embellish or alter the facts as your employer chose to do."
This kind of incident reflects "one of the great challenges of the digital age," said Lee Rainie, director of the Pew Research Center's Internet & American Life Project.
"Organizations often want all the advantages of social media to promote themselves and their missions, but struggle to figure out the boundaries for their employees. The law sometimes is not at all clear about where the border between free speech and organizational rule-making can be drawn," Rainie said.