Frank Thomas Sues Chicago White Sox Over Jersey Sale Cash

Frank Thomas donned a White Sox uniform for 16 seasons, but now he's taking his former team to court ... TMZ Sports has learned the Hall of Famer filed a lawsuit against the club, insisting they're using his name to sell merch without permission!

Thomas filed suit last week in Illinois, and he's targeting not just the White Sox, but Nike and Fanatics, too ... and the beef is over the Sox "City Connect 2.0" jersey, which the team announced in April 2025.

In the complaint, Thomas claims his name and number 35 were featured on some of the uni tops that were put up for sale, despite never getting consent, according to Thomas.

The Big Hurt says the White Sox -- and the retailers -- likely raked in huge profits, while he says he received "no compensation" for the use of "Thomas" and his iconic number 35.

As a result, Thomas claims he has "suffered economic detriment," including "loss of licensing revenue, and economic value associated with controlling the commercial use of his name and likeness."

“The complaint we filed alleges violations of the Illinois Right to Publicity Act," William T. Gibbs, a law partner at Corboy & Demetrio, told us. "Companies may not profit from anyone’s identity without their permission. We believe our filing speaks for itself.”

We spoke with Thomas' lawyer, Thomas Demetrio, who told us that Frank actually sent a cease and desist letter to the parties to halt production of the jersey -- but says that it "fell on deaf ears."

It's unclear how much money Thomas and his legal team are seeking ... Demetrio said until an accounting of the sales is done -- they won't know the exact amount.

He also said that Thomas is not upset with the White Sox, this is a business lawsuit, and that fans shouldn't be upset with Frank.

"They may ask 'does he really need the money,' that's not the issue," Demetrio said. "People shouldn't slam him for protecting his image, name and hard work. Hopefully fans will side with Frank."

Thomas is one of baseball's most prolific sluggers ever.

The 57-year-old was drafted to the South Side of Chicago in 1989, making his Major League debut in 1990. Thomas left Chicago in 2005, bouncing between the Blue Jays and the Athletics.