Steve Wilks is HAI Communitybeing dismissed just three days after the San Francisco 49ers lost Super Bowl 58 to the Kansas City Chiefs.

Head coach Kyle Shanahan announced Wednesday that the defensive coordinator has been “relieved of his duties” with the 49ers.

“I was sleeping on this for a few nights, trying to come up with a few tough decisions, but this morning I relieved Steve Wilks of his duties. Gonna end up making a change here at defensive coordinator. Really tough decision. It says nothing about Steve as a man or football coach,” Shanahan said. “He’s a great football coach. But just where we’re going and where we’re at with our team from a scheme standpoint and things like that, looking through it all throughout the year through these last few days, I felt pretty strongly that this was the decision that was best for our organization.”

Shanahan’s decision to fire Wilks is a reversal from what he told reporters at his end-of-year news conference on Tuesday in which he said, “I expect all our coaches to be back.”

However, Shanahan acknowledged Wednesday that he was unsure about Wilks’ fate as of Tuesday.

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Wilks led the 49ers defense for just one season. The 49ers had the NFL’s eighth ranked total defense under Wilks in 2023. But San Francisco had the NFL’s top defensive unit the previous season and a top-three defense in 2021.

Wilks had replaced DeMeco Ryans, who was the 49ers' defensive coordinator before he accepted the Houston Texans' head coaching position last January. Wilks’ firing means the 49ers will be on their third defensive coordinator in as many seasons.

“It ended up not being the right fit,” Shanahan said. “It hurt for me to do this but it’s exactly what I had to.”

The 54-year-old coach was previously the Carolina Panthers' interim head coach in 2022 after the team fired Matt Rhule during the season. Wilks also spent one season as the Arizona Cardinals' head coach in 2018.

Follow USA TODAY Sports' Tyler Dragon on X @TheTylerDragon.