Avril, who was released by the Seahawks earlier this month, discussed the conclusion of Super Bowl XLIX during a podcast Thursday with NFL Network, adding that Seattle would have won at least one more championship under Carroll if not for Malcolm Butler's goal-line interception.
The Seahawks were closing in on a second consecutive Super Bowl victory when, trailing by four points, they advanced the ball to the Patriots' 1-yard line with 26 seconds remaining. But rather than run the ball with five-time Pro Bowler Marshawn Lynch, Carroll called for a pass from Russell Wilson, who was picked off by Butler.
"I do think the team would have bought in more to what Coach Carroll was saying," Avril said, "instead of going the opposite way of, 'Hey, this is what we thought the foundation of the team was.' That's not what happened in that particular play.
"So I think guys started questioning him more, more so than actually following his lead if we would have won that Super Bowl."
ESPN reported in 2017 that Butler's interception and Carroll's approach with Wilson were the sources of tension within Seattle's locker room, specifically with veteran defensive players like star cornerback Richard Sherman. Avril seemed to confirm some of those aspects Thursday, citing "the message" of the defining play from the Super Bowl loss.
"The situation sucked regardless of who took the blame," Avril said. "It's just the fact that we were so close and we weren't able to get it, so I think a lot of guys got turned off by the message."
Carroll, Wilson and Sherman all publicly denied any internal strife at different points last year. The Seahawks went 9-7 and missed the playoffs in 2017, ending a streak of five straight postseason appearances under Carroll. Avril and Sherman both have been released this offseason by the Seahawks, which also traded veteran defensive lineman Michael Bennett.
Avril, 32, reflected Thursday on his five-year stint with the Seahawks and on Butler's pivotal interception.
"Sometimes it's tough, because two [championships] is better than one, obviously," he said. "You think about what could have happened. If we win that Super Bowl, I think we probably would have won another one within the two years that went by."
Avril was released by the Seahawks with a failed physical designation on May 4. His football future had been in doubt since he suffered a career-threatening neck/spine injury in October, causing him to miss the final 12 games of the season.