As explained in the overview post, here, this is part of a series looking at the best and worst defensive performers over the past three combined seasons. Rankings are done by adding a player’s UZR with his aggregate positional adjustment so as to level the playing field with regards to difficulty. Essentially, it’s removing the grading curve.

Tonight, the fifth best player from 2007-9: 3B Ryan Zimmerman.

Zimmerman reached the fifth spot thanks to his 2007 and 2009 seasons, during both of which he posted UZRs over 17. He was no slouch in 2008, but it goes to show why we need to rely on more than just one season of defensive data to draw any decent conclusions.

A full time third basemen for the Nationals, Zimmerman received the same positional adjustment (pro-rated to his overall playing time) each year. In four reasonably full seasons so far, Zimmerman’s defensive numbers seem to yo-yo, alternating between slightly above average and extraordinary.

When his bat shows up to match a good year with the glove, as it did this year with career highs in both wOBA and UZR, Zimmerman is a superstar, eclipsing seven wins of value. Even in his worst season to date, last year, he’s managed to be above average both at the plate and in the field, and reduced playing time because of injury only managed to keep him at a 2.2 WAR, still an above average player.

Ryan Zimmerman is one of the stars of the game today. With the arrival of Stephen Strasburg next year, maybe some of the spillover spotlight will find its way to him and he’ll finally start getting his just due.