Over the course of baseball history, catchers are prone to injury and rapid decline.
When assessing this deal, it wouldn't be wise to judge San Francisco's commitment to Posey as the second-biggest deal ever for a catcher.
Instead, praise the Giants front office, specifically general manager Brian Sabean, for eschewing conventional thinking with the reigning NL MVP.
Posey's versatility, specifically his ability to play first base now and in the future, is the key to this contract paying big dividends for the defending World Series champions.
A quick look at Baseball-Reference.com shows that Posey isn't just a candidate to play first base when he ages (a la Mike Piazza), but rather a viable option there now.
In three seasons, two of which were shortened by minor league service time and injury, respectively, Posey has played 61 games at first base.
According to Baseball Info Solutions' defensive runs saved metric, he's a below-average defender at first. Of course, that doesn't mean he couldn't improve if given more time. Also, the numbers are prorated off only the 61 games. To be fair, it's too small of a sample size.
While his versatility makes him a safe bet to change positions and stave off wear and tear over the course of his prime, don't forget his biggest attribute: a power bat that can play at any position on the diamond.
His .957 OPS and 172 OPS+ in 2012 weren't just good—they were great. The OPS+ led the league.
Using Baseball-Reference.com's play index, it's easy to see how well Posey's bat can play at either first or catcher. Since 1901, here is where Posey ranks in OPS+ among first basemen or catchers in their age 22-25 seasons: 11th all time.
The names ahead of him in that top 10: Jimmie Foxx, Frank Thomas, Lou Gehrig, Johnny Mize, Albert Pujols, Will Clark, Fred McGriff, Hank Greenberg, Don Mattingly and Bill Skowron.
In short, those guys could really hit.
As can Posey.
For the San Francisco Giants, they're betting that their All-Star, MVP and Rookie of the Year winner can hit for a long, long time.
The commitment, in dollars and years, can be compared favorably to the deal Derek Jeter agreed to with the Yankees in 2001. Posey and Jeter play vastly different positions—though, to be fair, both are valuable up-the-middle players—but they represented so much in their early years in productivity and winning.
Over Jeter's first five years in New York, he helped lead the Yankees to four World Series championships, won a Rookie of the Year award and took home All-Star Game and World Series MVP honors.
Through three seasons in San Fran, Posey's resume is very similar. When you factor in the business side of long-term contracts, the Jeter-Posey comparison takes on even more weight.
Jeter was the future of the Yankees. Posey is the future of the Giants.
Considering the company he is in and his versatility, it's a bet worth making.