Both the Rams and 49ers have undergone some significant changes sine the two teams last met in Week 3. For Los Angeles, rookies have received more playing time, some players have switched positions, and, of course, the Rams have clinched their first NFC West title since 2003.

But no change appears to have been more significant for either team than San Francisco's trade for quarterback Jimmy Garoppolo. When the Niners acquired the signal-caller from the Patriots for a second-round pick at the trading deadline on Oct. 30, the move sent shockwaves throughout the NFL. And while San Francisco has only had Garoppolo behind center for four games, he's clearly an answer at the game's most important position.

"He's come in, he's played at a high level, which has helped a ton. He won his first game in there in Chicago and I think it gave the guys some energy and some confidence and we've gotten a little better each week since then," 49ers head coach Kyle Shanahan said. "I think our team has gotten healthier too than we were at the mid-point of the year, so that was good timing. Jimmy has played great, but the guys around him having been playing as good in this last month as they have all year."

Through five games — four starts — Garppolo has completed 69 percent of his passes for 1,268 yards with five touchdowns and three interceptions. Those are fairly remarkable numbers considering Garoppolo spent the entire offseason and the first two months of the regular season with another team.

Shanahan said Garoppolo got in position to start and be successful with a lot of hard work over the first few weeks following the trade.

"He grinded with our quarterback coach everyday about that. We went to a bye week and he stayed back around the bye week for a number of days so the quarterback coach could work some more and he's really just been preparing for that opportunity," Shanahan said. "We gave it to him for Chicago and each week he's learned more. He's gotten more used to it. He definitely played his best last week and I think it'll be a lot easier going into the offseason, the fact that he's had some time. Then we can really just start over, re-teach it to him and I think a lot more of it will stick."

It's easy to see just how dynamic Garoppolo can be as a quarterback, and L.A. head coach Sean McVay certainly has.

"I think when you just look at what Jimmy's done since he's been playing these last couple weeks — he definitely instilled a confidence and energy on their offense," McVay said. "I think Kyle does a great job putting them in good situations and he's distributing the ball to a variety of playmakers.

"You even hear some of the comments that his teammates are making in terms of just the confidence that he instills based on swagger and demeanor that he has," McVay continued. "They've been playing really good football behind his leadership offensively."

McVay added that Garoppolo's ability to change his arm angle and improvise in certain situations also sets him apart.

"They're changing the launch point with some of those run actions that are married with the play-action, where they're changing the launch point as far as a bootleg or some of those where you're actually setting up in the pocket," McVay said. "I think the skillset where he can kind of speed up his delivery at the top, he keeps his eyes down the field. Some of the off schedule plays he's made in red zone have been really impressive. He's definitely given them a spark. They're playing really well."

Garoppolo is currently under contract through just the end of this season. But it's fairly unrealistic to think he'll be playing for any other team anytime soon — whether by franchise tag or long-term deal. In that way, the Rams and 49ers appear set to renew a longstanding rivalry with two good, young quarterbacks for the foreseeable future.

"[T]o see them play the way that they are of late where you're looking at winning as many games as they have and in the fashion — very impressive," McVay said. "I think it says a lot about their team. They've got a lot of momentum right now and they're playing as well as anybody."

"I feel like we've gotten that feeling here over the last month and I love some of the players we've developed — some of the young guys have had opportunities to play all year," Shanahan said. "I really look forward to it helping us be a better team next year."