It's a good time to be a San Francisco Giants fan
That extra piece has a name. His name is Gerald Posey III but Giants fans just like to call him Buster. The guy hasn't even played two complete seasons in the majors (came up in the middle of the 2010 season and missed the majority of 2011) and he has a Rookie of the Year, Comeback Player of the Year, a batting title, a Silver Slugger, an MVP, and two titles. Oh yeah, and he hit a massive grand slam in the decisive game of last year 's NLDS.
There have been a few players in baseball history, mostly Yankees, that simply took over the majors and started winning when they showed up. Yogi Berra and Derek Jeter come to mind. Berra got two rings in his first four seasons and Jeter got two in his first three years. Clearly, the Giants have some work to do to match the accomplishments of those two Yankee dynasties, but fans have to be feeling pretty good with Posey locked up for the next nine years. Posey has the edge in terms of personal hardware; Jeter finished a paltry third in MVP voting his second full season and it took six seasons for Berra to win the award.
There is something special about having your catcher be your best player. He instills confidence in the pitching staff and the rest of the position players and the coaches have to respect that he can lead the league in hitting and bat cleanup while playing the most physically demanding and toughest position on the field.
For what it's worth, Buster Posey is NOT the best player in baseball. Mike Trout, Robinson Cano, and Justin Verlander all had higher WAR last season and Posey is well behind Yadier Molina on the list of best defensive catchers. But if I were Brian Sabean, there's no way I would trade him for any of those guys. Even with his injury history and risk of future injury at the catcher position, I'd still keep him behind the plate as much as possible too. Having an elite player and proven winner controlling a pitching staff and being involved in every single play of a game is just too valuable.