"I don't regret my decision," Thomas told ESPN's Josina Anderson. "If my teammates felt like it was toward them, I regret that part. But I don't regret doing that to Pete."
Thomas was carted off the field with his leg in an air cast in September, after he went down with a broken left leg that required surgery in the second half of a game against the Arizona Cardinals. He gave the middle finger in the direction of Seattle's sideline because he didn't think Carroll was being genuine when he showed concern on the field after the injury.
Thomas, in his first season with Baltimore, said he hasn't spoken to Carroll since the incident. The Ravens face the Seahawks in Seattle on Oct. 20.
"I gave Pete the middle finger because I felt like he wasn't being honest with me," Thomas said.
When Thomas took heat for the gesture last season, Carroll said people needed to cut him "a little slack."
"People that are criticizing whatever happened don't understand," Carroll said. "This was an earth-shattering moment for a kid. He's trying to play this game he loves, and all of sudden this happens again. He knew exactly what happened to him, so he went right to what it's going to take to get back."
Thomas was one of the best defensive backs in Seahawks history. He made six Pro Bowls in his nine seasons with the team and was named first-team All-Pro three times. His 28 career interceptions rank third among all players since 2010, when he was drafted by Seattle with the 14th overall pick out of Texas.
He left the Seahawks in free agency, signing a four-year, $55 million contract with the Ravens in March.
"I think my time just ran out," Thomas said. "Pete and the front office didn't value me like they used to, and I just talked to Coach Carroll, and he was saying how he was trying to get me in the plans of getting a new contract. But I got hurt the next week. I think I hurt myself too by my actions getting carted off the field."
Thomas won a Super Bowl with Seattle in February 2014 and signed a four-year, $40 million contract extension a few months later.
But his relationship soured last year. Thomas had a contract dispute with Seattle that led him to skip all offseason activities, training camp and preseason in 2018.
Thomas said he didn't see eye-to-eye with Carroll on many issues, including work ethic.
"We got to walk with each other the rest of our lives because we won a Super Bowl together," Thomas said. "But they'll love you one minute and then hate you the next. That was our relationship."