THOUSAND OAKS, Calif. -- Perhaps no head coach has ever turned an offense around as quickly and as impressively as Sean McVay already has with the Los Angeles Rams.

The Rams managed a mere 224 points last season, the lowest total by an NFL team since 2012. This year, they have already scored 142 points, 13 more than the second-place New England Patriots. Research from the Elias Sports Bureau reveals that McVay, hired at the age of 30 to fix a broken offense, has the third-most points through a coach's first four career games since the merger in 1970.

The only two ahead of McVay: Bill Callahan, who got 162 points in his first four games with the 2002 Oakland Raiders, and Mike Martz, who got 160 points in his first four games with the 2000 St. Louis Rams. But Callahan was taking over a Jon Gruden-led Raiders team that finished fourth in the NFL in scoring the prior season, with established skill-position players such as Rich Gannon, Charlie Garner, Jerry Rice and Tim Brown. Martz took the controls for "The Greatest Show On Turf," with Kurt Warner, Marshall Faulk, Isaac Bruce and Torry Holt leading the way.

The Rams team McVay inherited? It finished last in the NFL in yards after each of the previous two seasons and outside the top 20 in offensive DVOA (Defense-adjusted Value Over Average) after each of the previous 10 seasons. The Rams' starting quarterback was only 22, the offensive line was a mess, the receiving corps was devoid of premier talent, and the running back was coming off a very unproductive season.

Now, suddenly, the Rams -- 3-1 coming off a big road win over the Dallas Cowboys -- are an offensive juggernaut.

Not that McVay will take any credit.

"I think what good coaches do is they put their players in situations to have success, but ultimately those players are the ones that are making those plays," McVay said. "You feel fortunate to be a part of that. I think the players have done a good job, but I also can't say enough about our coaching staff."

It really has been a group effort, but it began with McVay, whose January hire kick-started a top-to-bottom offensive overhaul that was desperately needed for this floundering franchise. Here, we'll take a look at the five biggest reasons the Rams have gone from the NFL's worst offense to (so far) the NFL's best offense in a matter of months.

5. A better group of receivers: The Rams replaced Kenny Britt, Brian Quick and Lance Kendricks with Sammy Watkins, Robert Woods and Gerald Everett, the athletic rookie tight end who was selected 44th overall.

Watkins gave the Rams the legitimate No. 1 receiver they hadn't had in years. Woods provided the sure-handed, precise route runner they desperately needed. But they also got a major steal in the third round of the draft, when they selected Cooper Kupp out of Eastern Washington. Kupp, already 24, is as polished as a rookie receiver can be. That entire group -- plus Tavon Austin, who has been relegated to a backfield decoy, and Tyler Higbee, another young athlete at tight end -- has contributed. Watkins, Woods and Kupp already have double-digit receptions.

4. A significant upgrade at left tackle: Perhaps no team improved at one position more than the Rams did at one of the game's most important spots. They replaced Greg Robinson, one of the game's worst left tackles, with Andrew Whitworth, one of the game's best. They guaranteed $15 million to a 35-year-old offensive lineman, but it was worth it.

Whitworth has allowed one pressure through his first four games, according to Pro Football Focus. His presence at left tackle, not to mention his willingness to mentor others, has made the entire offensive line better. Jared Goff has taken only four sacks in four games after taking 26 of them in seven games last season. Gurley is averaging 4.2 yards per carry after averaging 3.2 yards per carry last season. John Sullivan has also been a nice addition at center.

3. Gurley got better: Yes, Gurley was victimized by a bad offensive line and a nonthreatening passing attack that made it easy for defenses to stack the box. But Gurley also missed his fair share of holes. Dating back to training camp, though, Gurley has been hitting holes quickly and decisively. He's running with a lot more confidence, and he has developed into a major threat as a receiver.

Gurley gained only 885 rushing yards last season, the lowest ever by someone with at least 275 carries. He made up for it somewhat by making 43 catches for 327 yards. This season, though, Gurley has hauled in 20 of his 22 targets for 234 yards. He has gained more than 100 yards on the ground in back-to-back games after going 20 straight games without reaching triple-digit rushing yards. And he leads the NFC in scrimmage yards with 596.

2. Goff got way better: Goff bought in from day one, since the afternoon of Jan. 5, when he studied film with McVay a week before he was hired. When NFL rules kept him from interacting with his new coaches in the winter, Goff ironed out his throwing mechanics at the acclaimed 3DQB. In the spring, he basically lived at the facility, studying the new playbook and familiarizing himself with new teammates.

So far this season, Goff has done nothing but make sound decisions and execute precise throws. He leads the NFL with 9.2 yards per attempt and has a 61.5 Total QBR, eighth-highest in the NFL through the first four weeks. Goff has seven touchdowns, two more than he had all of the previous season, and only one interception. His quarterback rating is 112.2, nearly double the 63.6 mark from his rookie season.

1. McVay implemented a great system: McVay has made the game a lot easier for Goff and has designed creative ways to get Gurley touches, whether it's creating the threat of a jet sweep with Austin or drawing up deceiving wheel routes or setting up screens off play fakes. The biggest key, in the words of McVay, are "plays that start out the same but are different."

A key staple of that is bunch formations that have receivers lining up tight with the offensive line, with an ability to run an assortment of passing and running plays off that. Because of that, play-action has been very effective as well. Another thing McVay and the new coaches did: Hammer home the fundamentals and demand perfection.

Said Austin: "He works us to death in practice. He works us 'til we get it. ... He demands professionalism. That’s what I like about him."