The NFL Live crew weighs in on how different the Niners' season could have been with Jimmy Garoppolo as their Week 1 starting QB. (1:35)

Even in a year when teams like the Rams and Texans have turned into entirely different offenses overnight by virtue of swapping in a quarterback or a head coach, it has been shocking to see what has happened to the 49ers since Jimmy Garoppolo made his way into the lineup. The simplest number is four: Garoppolo took over a team that had gone 1-10 under the stewardship of C.J. Beathard and Brian Hoyer and has won each of his first four starts with the 49ers, punctuated by a 44-33 win over the Jaguars and their top-ranked pass defense last week.

It appears that 49ers general manager John Lynch may have accomplished one of the hardest things to do in sports: get one over on Bill Belichick. If Garoppolo is as good as he has looked in his first six starts as a pro in New England and San Francisco, the 49ers made out like bandits in acquiring the 26-year-old for a mere second-round pick. The entire trajectory of this franchise has been transformed in a matter of weeks.

Let's take a look at Garoppolo and the 49ers after his first quarter of a season at the helm in San Francisco. Has he shown enough to already be considered a franchise quarterback? What happens from here on out with him and the 49ers? Let's answer some questions that Lynch and Kyle Shanahan are very excited to be asking.

Has Garoppolo really been that great so far?

Well, yeah. Since he took over as the starter in Week 13, you can make a case that Garoppolo has been the best quarterback in football. He ranks among the league leaders over that time frame in both completion percentage (69.0 percent, fifth) and yards per attempt (8.7, third), and rates as the league leader in Total QBR (82.1), nearly 10 points ahead of Ben Roethlisberger in second place.

The 49ers haven't been quite as productive on offense as those numbers would suggest by virtue of where Garoppolo has struggled. The red zone had been an issue for the 49ers in Jimmy G's three starts before the Jacksonville tilt. The 49ers pushed the ball inside the 20 a whopping 13 times in three games and scored exactly three touchdowns, producing an average of 3.9 points per red zone possession. The Jets were the only team in the league to stay under four points per red zone trip last season. This is how your field goal kicker goes 15-for-15 over a three-week span.

Red zone performance tends to catch up to a quarterback's performance over the other 80 yards of the field, though, and that's exactly what happened last week. The 49ers made six trips to the end zone and scored four touchdowns, throwing in a field goal and a tipped interception for an average of more than five points per red zone possession. If Garoppolo plays great football outside of the red zone, chances are he'll be great inside of it, too.

Think about who Garoppolo is doing this with, too. The 49ers are without Pierre Garcon, their presumed No. 1 receiver. Right tackle Trent Brown, one of the more underrated tackles in football, was struggling through a torn labrum before going on injured reserve on Dec. 15.

Garoppolo's top receiver right now is Marquise Goodwin, who was the No. 3 target on the Bills last season. Rookie fifth-rounder Trent Taylor has emerged as a useful slot receiver. Garrett Celek, a rare holdover to the Jim Harbaugh days, has 160 yards and pair of touchdowns at tight end with Garoppolo in the lineup. Fullback Kyle Juszczyk, signed to a much-derided deal this offseason, had 120 receiving yards in nine games before Garoppolo's arrival and suddenly has 176 yards in four games with the new quarterback. Garoppolo is making these guys look like superstars.

What's most striking? Garoppolo looks remarkably smooth for a player who has been working underneath Shanahan for only a few weeks. There aren't many of those frozen moments in which you see a young quarterback visually struggling with the progressions and frantically trying to find his open receiver. So much of what Garoppolo does feels on time and in stride. The two-minute drill he led to set up a game-winning field goal over the Titans was preternaturally cool and collected, a series of almost breezy completions over the middle. He looks every bit as good as his numbers.

How does he compare to other quarterbacks after six starts?

Going back through 2001, Garoppolo is just the third quarterback to start his career with six wins in six starts, joining Roethlisberger and Marc Bulger. Their careers obviously diverged in different directions, and both are possible for Garoppolo. Roethlisberger ended up on a perennial winner and has had consistent success for his entire career. Bulger struggled to stay healthy and went from playing in an excellent offense to struggling within a shell of a broken scheme on a roster stripped of talent.

In terms of performance, Garoppolo has the eighth-best passer rating (102.9) of any quarterback through their first six starts. Roethlisberger is on that list, which is a mixed bag. Let's run out the top 10 and how they performed over their next season's worth of starts:

Most of the quarterbacks weren't able to keep their previous level of play up, but they also remained effective. Matt Flynn looms as a cautionary tale, given that he looked like a possible franchise quarterback behind Aaron Rodgers and failed to impress with the Seahawks and then the Raiders. The 69.6 rating is for his seventh and final pro start, back as a member of the Packers. Given that Garoppolo already has looked impressive outside of New England, though, it's fair to point to Bulger as a more realistic floor comparison.

Rodgers, actually, looms as a comparison here for another reason.

What do the 49ers do with Garoppolo's contract?

San Francisco traded for Garoppolo during the fourth and final season in his rookie deal, and as a former second-round pick, the Eastern Illinois product has no fifth-year option language in his deal. When I wrote about this situation after the trade in October, I suggested that the 49ers were likely to franchise Garoppolo as a way of evaluating him through the end of the 2018 season before making a decision on his long-term future.

If they're confident after six starts, though, the Niners do have a precedent to consider. Under the previous collective bargaining agreement, the Packers sat Rodgers for the first three years of his deal behind Brett Favre before turning the reins over in his fourth year. Rodgers excelled during his first seven starts as a pro, and while Ted Thompson had Rodgers locked up for another year and a half at a base salary of just $680,000, the Packers GM used the leverage he had and his faith in Rodgers' ability to sign a bargain of a deal.

The 49ers are 4-0 since going to Jimmy Garoppolo as the starter. Will that continue in 2018? Photo by Robin Alam/Icon Sportswire

Rodgers signed a six-year, $68 million extension with $20 million guaranteed in an era where the cap was at $116 million. The deal essentially guaranteed Rodgers two years and left the Packers a series of team-friendly options afterward, which they rode to a Super Bowl. The contract was so good that Rodgers' third deal, signed in 2013, was again reasonable for a quarterback who might have approached $50 million per year if he hit the open market that year.

The Niners don't have quite as much leverage over Garoppolo, but the idea is the same: If you believe you've found your guy and are willing to bet your job on it, there's no better time to make a move than today. Lynch would owe Garoppolo something in the range of $50.5 million over the next two seasons if he went with back-to-back franchise tags. The 49ers have $117.9 million in cap space next year. So could the 49ers work out a deal in which Garoppolo gets $45 million guaranteed at signing, all over the next two seasons, on a five-year, $126 million extension?

Once players such as Rodgers and Russell Wilson sign their new deals, $25 million isn't going to seem like a huge extension for quarterbacks.

Why did the Patriots trade Garoppolo for a second-round pick?

I wrote about the logic with Garoppolo's deal in October, but the Patriots left themselves with no leverage. They either turned down offers this past offseason or never actively entertained deals in the hopes of signing Garoppolo to an extension this season. Perhaps they wanted to see if Tom Brady would be hit by Father Time and suffer a Peyton Manning-esque falloff overnight.

Instead, Brady has been great and is the favorite to win league MVP. The Patriots weren't able to come to terms on a deal with Garoppolo and didn't have any better alternatives. Letting Garoppolo leave in free agency would have set the Patriots' max compensation as the 97th pick in the third round of the 2019 draft. By trading Garoppolo now, the Pats knew they were likely to come away with a pick in the 33-40 range of the 2018 draft, a far more valuable selection.

Are there any reasons to be concerned with Garoppolo?

Of course.

Six starts is still an incredibly small sample size, even if Garoppolo has looked great. One concern is still that we don't really have a good grasp on Garoppolo's ability to avoid injuries, given that he separated his shoulder halfway through his second start with the Patriots. It's way too early to say that Garoppolo is injury-prone or doesn't have the ability to avoid the big hits that are likely to cause injuries, of course, but we don't have much information. Every time Garoppolo makes it through a game unscathed is a useful piece of information in projecting his likelihood of staying healthy.

We also really haven't seen a situation in which Garoppolo has needed to throw while behind several scores to catch up, given that he has exclusively been either way ahead or in competitive games during his brief pro career. That's not a knock on Garoppolo, of course -- he shouldn't be blamed for keeping things close or getting out to a lead -- but it will be interesting to see how he responds when other teams know he has to throw.

The reality we've learned from 2016 and 2017 is also worth keeping in mind: quarterbacks can look like upper-echelon franchise passers one year and totally lost the next. Think about Derek Carr, who was a viable MVP candidate for most of last year before a broken pinkie and a fractured fibula derailed his season. This year, Carr has looked wildly inconsistent without deposed offensive coordinator Bill Musgrave, and whether he's hurt or lacking confidence, the 26-year-old looked like a flailing rookie during the Christmas night loss to the Eagles.

Everyone in the league would have agreed that the Raiders were right to pay Carr the going rate for franchise quarterbacks this offseason after three consecutive seasons of growth. Now, after a huge step backward, the Raiders are locked into Carr at a $25 million cap hit next year before they can even think about making a change under center. Jack del Rio is in danger of getting fired. Carr probably will break right and re-emerge as a useful starter next season, but what if he doesn't?

Just because a QB has a breakout season doesn't mean things stay great. Ask Derek Carr. AP Photo/Ben Margot

He's not the only one. Dak Prescott was one of the most impressive rookies in league history last year and some Cowboys fans promptly wanted to bench him after a mediocre three-game stretch this season. On the flip side, Case Keenum was a journeyman backup this time last year, buried on the Rams' depth chart behind a disastrous rookie season from Jared Goff. Now, Goff and Keenum might be favorites to meet in the NFC Championship Game after their Pro Bowl-caliber seasons.

It is incredibly difficult to judge quarterbacks in the NFL, and it's often going to be easier to poke holes in a guy than it will be to know that he's your franchise quarterback. Ask the Browns, who raised legitimate question marks about Carson Wentz and Deshaun Watson, opted to go after midtier targets instead, and ended up wasting two years of time while losing 30 of 31 games.

At some point, every organizational rebuild has to make a bet on their guy and run the risk of front-office firings if things don't work out. The 49ers dipped their toes into the water by sending a second-round pick to the Patriots for Garoppolo. Now, four starts later, the water seems quite comfortable. It might not work, but there are no guaranteed solutions under center. There's little reason to think that the Niners won't -- or shouldn't -- build their future around Jimmy G.

Does this accelerate the 49ers' competitive timeline?

Everything is different now.

Before the Garoppolo trade, the 49ers were going to hit the 2018 offseason with a high draft pick and an outside shot at getting Kirk Cousins. The most plausible outcome was that they would draft one of this crop's many quarterbacks in the top five and spend a year developing them before really expecting to compete in the 2019 season. Things might always break differently, of course, but that was the most likely path to contention for the 49ers.

Now, the path accelerates. Garoppolo has a limited team looking like a viable contender; even if they lose on Sunday, the 49ers will have gone 4-1 with a pair of victories over AFC playoff teams with Garoppolo at the helm. The glowing remarks about Garoppolo from the players he has gone up against or played alongside are going to get around. Free agents are going to want to play with Garoppolo in free agency. The days when the 49ers had to massively overpay to convince veteran free agents to come to San Francisco are probably over.

With six first-round picks on defense (pending the return of Eric Reid), the 49ers can safely afford to put their massive cap surplus toward improving the offense. Lynch invested in a pair of free-agent wideouts with Garcon and Goodwin, and Taylor has shown promise in the slot, so it wouldn't be a surprise to see him look for a tight end to supplement Celek and George Kittle. Trey Burton has excelled in Philadelphia in a limited role behind Zach Ertz, and it would hardly be a surprise to see the 49ers pay him starter-caliber money to see if he can break out with more snaps.

Running back seems like an even more interesting proposition. The 49ers haven't committed to Carlos Hyde, who was inherited from the old regime and has been strictly competent for most of the year. Shanahan loves pass-catching backs with the patience to run a zone scheme, and there's one very significant option out there. The 49ers are one of the few teams with both the need at running back and the cap space to target Le'Veon Bell. If he doesn't come to terms with the Steelers, the Niners could very viably target Bell at a $15 million-per-year salary without squeezing their cap situation at all.

By drafting an interior lineman like Notre Dame guard Quenton Nelson, the 49ers would suddenly look very exciting on offense. A backfield with Bell and Juszczyk behind Garoppolo? A full complement of receivers in Garoppolo's first full season at the helm? San Francisco would still need to invest in its secondary, where cornerback remains an issue, but the offense would be able to hold up its end of the bargain if everyone stays healthy.