EARTH CITY, Mo. -- Before the start of the 2013 season, the St. Louis Rams attempted to build their offense around quarterback Sam Bradford. They drafted receivers Tavon Austin and Stedman Bailey and signed offensive tackle Jake Long and tight end Jared Cook with the intent to spread things out and have Bradford pile up the video-game numbers he did when he won the Heisman Trophy at Oklahoma.

The experiment was a monumental bust and lasted all of four games before Rams coach Jeff Fisher scuttled it. Fisher and the Rams went back to a grind-it-out philosophy that brought stability to the offense, but mediocre results in the win column.

Three games later, on Oct. 20, 2013, Bradford played in what would be his final regular-season game as a member of the Rams against Carolina. He tore the ACL in his left knee and missed the rest of that season. He bounced back in time for the 2014 preseason only to suffer the same injury again. Of a possible 80 games, Bradford played in 49 in five seasons.

On Tuesday, the Rams sent Bradford to Philadelphia in exchange for quarterback Nick Foles. The Rams also received Philadelphia's 2015 fourth-round pick and 2016 second-round pick, the Eagles got the Rams' 2015 fifth-round pick. If Bradford plays less than 50 percent of the snaps in 2015, the Eagles get a 2016 fourth-round pick from the Rams. If Bradford does not play this season, the Eagles get a 2016 third-round pick from the Rams. If Bradford plays more than 50 percent of the snaps in 2015, the Eagles get no additional picks.

In Foles, the Rams are getting a fresh start at the game's most important position, albeit one with limitations who has yet to prove he can consistently perform in an offense outside of what Chip Kelly does in Philadelphia.

Foles should be an upgrade over Bradford by the simple act of being healthy and cost-effective. His 2015 cap number is just $1.542 million. Although Foles is coming off a clavicle injury, his medical history doesn't approach Bradford's. But really, if the Rams are to become what Fisher wants them to become, Foles should only play a minor role.

In trading Bradford, the Rams gained nearly $13 million in salary-cap savings, which puts them in the range of $28 million in available space. Time and again, Fisher has emphasized the need for his team to win with a dominant defense and a power running game.

"I don't think it's any different than anybody else," Fisher said at the scouting combine in February. "It's a run game. You need to run the football and you need to complement your play-action game to the run game and play good defense and play good special teams. You know, everybody will tell you, if you got a top-five or six defense and you can run the football, you've got a chance to be in the final four. That's the very basic theory."

It's a theory that might sound good on the surface, but is much more difficult in execution. In Seattle, that very basic theory has worked wonders, but only because the Seahawks have a truly dominant defense and a run game to match.

In three seasons with Fisher as the head coach, the Rams have averaged 106.3 rushing yards per game, which ranks 19th, and an average of 4.1 yards per carry, which ranks 17th. Meanwhile, Seattle's rushing attack is first in yards per game and second in yards per carry in that span.

The pieces for a dominant defense look to be in place, but if the Rams are to become what Fisher wants, they must make haste to ensure the running game can meet that standard.

As the Rams were pulling off the Bradford-Foles swap Tuesday afternoon, the rest of the league was busy signing top free agents. After releasing center Scott Wells and tackle Jake Long and with Joe Barksdale and Davin Joseph set to hit unrestricted free agency, the Rams could need as many as three new starters on the offensive line.

However, now that the Rams have the money, many of the types of players who would seem to fit into what the Rams want are already gone. Center Rodney Hudson is headed to the Oakland Raiders, the San Diego Chargers landed guard/tackle Orlando Franklin, and guard Mike Iupati is off to Arizona. Signing high-priced offensive linemen hasn't worked out well for the Rams in the past, but if they're willing to make a bold move by ridding themselves of Bradford, this is the time to buoy those moves by pushing their chips in and trying to legitimately become what Fisher wants.

Taking it a step further, while the Rams like their young group of running backs, including Tre Mason, chasing a top back such as DeMarco Murray or even, as crazy as it sounds, Adrian Peterson, would make even more sense. Fisher's Tennessee teams enjoyed their greatest success in the prime years of Eddie George and Chris Johnson.

Fisher and his staff are entering their fourth season without so much as a winning record to show for it. Along the way, we've only seen small glimpses of the Rams becoming what he has envisioned since he arrived in 2012.

For better or worse, trading Bradford gives the Rams the money and opportunity to help realize that vision. It's incumbent on Fisher and his group to see it through before it's too late and, like Bradford, they too are on their way out the door.