SANTA CLARA, Calif. -- With seven starts to his name after sitting behind an NFL legend for the better part of three years, a promising young quarterback once earned a lucrative contract extension without much of a sample size.

At the time the deal was considered eye-opening, but it didn't take long before the Green Bay Packers' first contract extension with quarterback Aaron Rodgers became a major bargain compared to the big money being handed out to other top signal-callers around the league. That all happened back in 2008. By the end of 2009, Rodgers had taken Green Bay to the postseason. By 2010, he had led the Packers to a Super Bowl championship, and a year later he was named league MVP.

If the first part of that equation sounds familiar, it should. The latest version of it just played out on Thursday afternoon as the San Francisco 49ers agreed to terms with their own promising quarterback, Jimmy Garoppolo, on a record-setting five-year, $137.5 million deal that is expected to pay out just shy of $90 million in the first three years, according to ESPN's Adam Schefter.

Much like Rodgers in 2008, Garoppolo has seven NFL starts to his name -- five with the 49ers and two with the New England Patriots. Garoppolo spent more than three years sitting behind Tom Brady, like Rodgers once did behind Brett Favre. And now there are some wondering how the Niners can justify a massive contract for a player who has yet to prove he can win over a long period of time?

The answer to that is simple: Garoppolo's five-game stretch as the team's starter to close the season, combined with his instant chemistry with his teammates, has led the Niners to the conclusion they have their own version of Rodgers. Which is to say they believe Garoppolo is the type of quarterback who can elevate the players around him and be the focal point of a team that competes for championships on a consistent basis.

That belief is rooted in what Garoppolo was able to do in his short stint as the starter. First and foremost, he took a 1-10 team and led it to five consecutive victories to close the season, including wins against the playoff-bound Tennessee Titans and Jacksonville Jaguars. Those five wins matched the total the Niners had posted in their previous 34 games combined.

Further, Garoppolo threw for 1,542 yards in those starts, a franchise record for most passing yards by a quarterback in his first five starts with the team. In 23 games with seven starts between the 49ers and Patriots, Garoppolo has completed 67.3 percent of his passes for 2,250 yards with 12 touchdowns and five interceptions for a passer rating of 99.7 and a 77.7 QBR. Garoppolo is 7-0 as an NFL starter.

Considering Garoppolo hasn't even had the chance to spend a full offseason in coach Kyle Shanahan's offense, the Niners also have reason to believe he is only going to get better, especially as they bolster his supporting cast.

Of course, Garoppolo hasn't yet had the chance to prove he can turn his small flashes of success into consistent production, though he's looking forward to the chance.

"I’ve heard talks about sample size," Garoppolo said after the season finale. "It’s one of those things you can’t really control how much you play or when you play, but when your number’s called, I think if you make the most of your opportunities in this league, that’s what makes good players. That’s what I’ve tried to do in my short time being a starter, and good things have come from it."

Garoppolo's deal undoubtedly caused jaws to drop because he became the NFL's highest-paid player. That's a title he probably won't hold for long. Kirk Cousins is expected to be the centerpiece of a competitive bidding war as soon as he hits the open market in March. He could easily surpass Garoppolo's deal a little more than a month from now.

Also, both the Atlanta Falcons and, fittingly, the Packers, have made it clear that they intend to sign quarterbacks Matt Ryan and Rodgers to big-money contract extensions this offseason. Pittsburgh's Ben Roethlisberger and Seattle's Russell Wilson also could be in line for new deals sooner than later. It's not out of the question that Garoppolo's deal will be surpassed multiple times before this offseason comes to a close.

In the meantime, the Niners have put themselves in an ideal position. While we don't yet know how Garoppolo's contract breaks down, the Niners have well over $100 million in salary-cap space. If they wanted, they could easily put a huge cap number on Garoppolo in the first year of this deal and still not have it affect their ability to build around him.

With the stability the Niners now have at head coach (Shanahan), general manager (John Lynch) and quarterback (Garoppolo), they are also now a more attractive destination for top free agents.

Make no mistake, Garoppolo still has plenty to prove before he can safely be tossed in the upper echelon of the NFL's top quarterbacks, even though he's now being paid like one. There's inherent risk in paying Garoppolo this kind of money without him having a more extensive resume.

But if Garoppolo can build on what he's already done and the Niners can add talent around him, there's a very real chance this contract will someday look like a pittance if the Niners and Garoppolo go back to the bargaining table (he'll only be 31 at the end of this contract).

After all, the best deals are always the ones that pay a premium for what a player will do rather than what he's already done.