ST. LOUIS — Rob Ryan won't be the St. Louis Rams' new defensive coordinator after all.

The Rams announced on Tuesday that the outspoken Ryan wasn't a good fit to run the team's defense.

Ryan ran a 3-4 defense the past three seasons with the Dallas Cowboys. The Rams run a 4-3 defense, and clearly have 4-3 personnel.

The Rams never made an official announcement of Ryan's hiring, but ESPN and other media outlets widely reported last Friday that he would be hired.

Rams coach Jeff Fisher continues his search for a defensive coordinator.

The Rams defense was coached by committee last season after defensive coordinator Gregg Williams was suspended by the NFL for his role in the New Orleans Saints' bounty scandal.

The Rams announced earlier this month that Williams wouldn't be back with the team next season. They also announced that Williams' son, Blake, who made most of the defensive calls in his father's absence, wouldn't be back.

Gregg Williams is reportedly close to being hired by the Tennessee Titans as the teams assistant head coach, but no hiring can take place until he is reinstated by NFL commissioner Roger Goodell.

Ryan, the son of longtime NFL coach Buddy Ryan and the twin brother of New York Jets coach Rex Ryan, boldly predicted, "I'll be out of work for like five minutes,'' when he was fired by the Cowboys on Jan. 8.

That five minutes is looking more like several weeks at best at this point.

The Rams have hired veteran NFL assistant Frank Bush to serve as their linebackers coach.

Bush's NFL career has included stints as a player, scout, position coach and coordinator.

He spent the last two seasons in Tennessee, and prior to his time with the Titans, Bush worked four seasons with the Houston Texans, including two as defensive coordinator.

"I'm extremely excited to add Frank to our staff," Fisher was quoted in a press release by the Rams. "Frank brings a wealth of experience and has a long history of success. Players respect him and our linebackers are going to enjoy playing for him."

With Bush as their defensive coordinator in 2009, the Texans established new franchise lows for fewest points allowed per game (20.8) and yards allowed per game (324.9).

Before joining the Texans, Bush spent three seasons with the Arizona Cardinals as linebackers coach. He was tabbed as assistant head coach for his final year.

Bush spent nine seasons coaching on Mike Shanahan's Denver Broncos teams from 1995-03 in a variety of capacities.

In his time with Denver, Bush earned two Super Bowl rings (XXXII and XXXIII).

Bush started his coaching career with the Houston Oilers as the linebackers coach from 1992-94. He worked with Fisher during the last two years of that stint.

Bush was a three-year starter at linebacker for North Carolina State and was a fifth-round selection of the Houston Oilers in the 1985 NFL Draft.

He earned all-rookie honors in his first season before an injury in his second campaign ended his playing career.

Bush stayed with the Oilers following his retirement as a player, joining the front office as a college scout (1987-92).

Contact reporter Steve Korte at skorte@bnd.com or 239-2522.