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Midway through their inaugural season as the San Francisco 49ers brain trust, freshman general manager John Lynch and rookie head coach Kyle Shanahan had to know they were going out on a limb—some might have considered it a twig—by acquiring and then eventually paying quarterback Jimmy Garoppolo.

When they gave the famously savvy New England Patriots a second-round pick in exchange for Garoppolo, he had two career starts under his belt. And when they handed the second-round Eastern Illinois product a five-year, $137.5 million contract just three months later, he had thrown just 12 career touchdown passes at the age of 26.

Then, he missed almost all of what was supposed to be his first full season as an NFL starter as a result of a torn ACL. And he followed that up this year with an inconsistent start that featured nearly as many interceptions (six) as touchdowns (seven) and an unimpressive passer rating (90.8) through six games.

At that point, it was fair to wonder if Garoppolo would ever pan out for the 49ers. It was reasonable to ask if Lynch and Shanahan erred by investing so heavily in a relatively unproven commodity.

In two months, that has all changed.

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Many of you might still view the 49ers as a team driven by their fierce, talented defense. And you might still view their offense specifically as a unit that is guided by a top-notch running game.

And sure, the defense—which surrendered a tied-for-league-low 4.7 yards per play and ranked tops in the NFC in terms of DVOA (defense-adjusted value over average) at Football Outsiders—is damn good. Ditto for an offensive backfield that averaged an NFC-best 144.1 rushing yards per game during the regular season.

But the top-seeded 49ers wouldn't be where they are now if not for Garoppolo. No way they'd have home-field advantage throughout the NFC playoffs, no chance they'd be favored by a full touchdown in the divisional playoffs. And without Garoppolo, they almost certainly wouldn't have the second-best Super Bowl odds among the elite eight.

Ever since that rocky start, Garoppolo has completed 69.6 percent of his passes for an average of 8.6 yards per attempt (the highest mark in the NFC dating back to Week 8). He's thrown 20 touchdown passes to seven interceptions, and his 108.1 passer rating ranked fourth among 33 qualified passers in that span.

Since Week 11, Garoppolo has completed a league-best 76.2 percent of his deep pass attempts for a passer rating of 117.7 on throws that travel 15-plus yards.

And while he did take too many sacks down the stretch—only four quarterbacks were taken down more than him in the second half of the season—he's still highly rated and extremely accurate under pressure.

And he was often at his best when it mattered most.

Among 29 quarterbacks who threw at least 40 passes in the fourth quarter or overtime of one-score games, Garoppolo ranked sixth with a passer rating of 107.8 under those circumstances—and that mark skyrocketed to 117.8 during the final seven games of the year.

Meanwhile, his season-long third-down completion percentage of 69.2 ranked No. 1 among 36 quarterbacks with at least 50 attempts under those circumstances.

Those concerned that Garoppolo might not be ready for the pressure associated with playoff football should take all of that into account, as well as the fact that he was at his best in a critical Week 17 prime-time victory over the division-rival Seattle Seahawks.

Literally. It was the highest-rated game of his career at Pro Football Focus.

Garoppolo finished the season with a tied-for-league-high nine triple-digit-rated performances, and four of those games just happened to be his last four appearances of the season against opponents that made the playoffs. In those late-season matchups with the Seahawks, New Orleans Saints, Baltimore Ravens and Green Bay Packers, Jimmy G completed 74.5 percent of his passes, averaged a ridiculous 10.7 yards per attempt and posted a passer rating of 128.4. And three of those outings came away from home—not that he has to worry about that between now and Super Bowl LIV.

And that's got to be the goal now, if not the expectation—especially with Drew Brees and the Saints out of the way. The 49ers are heavily favored against the Minnesota Vikings, they beat the Seahawks on the road two weeks ago, and they crushed the Packers in November.

Starting quarterbacks making their first playoff starts are always a risk. Just look at Josh Allen last week, or Mitchell Trubisky, Deshaun Watson and Lamar Jackson last year. But Garoppolo's case feels different. And let's not forget that the 28-year-old is a two-time Super Bowl champion. He didn't throw any playoff passes in New England, but he did learn from Tom Brady and Bill Belichick.

You know the 49ers for their world-famous defense, which gave up just 12.8 points per game in the first half of the 2019 season. But that unit actually surrendered 26.0 points per game in the second half of the year, which was the ninth-worst mark in the NFL.

You might also know the 49ers for their highly touted running game, which averaged 171.1 yards per game in the first eight weeks of 2019. But that unit only mustered 117.0 yards per affair the rest of the way, which ranked 13th.

The truth is Garoppolo has been the key to San Francisco's success for weeks now, if not months. That means the gamble from Lynch and Shanahan has already paid off.

Now, we'll see if they hit the jackpot.

Brad Gagnon has covered the NFL for Bleacher Report since 2012.