Big and exciting news out of Los Angeles today. The cash-poor but deadbeat-owner rich Dodgers and soon-to-be free agent (one remaining year of arbitration) Matt Kemp agree to a reported eight-year, $160 million contract extension! The deal is the largest in Dodgers history, eclipsing the time they traded Kevin Brown for the Sierra Madre Mountains and Tommy LaSorda’s deal with the devil.

Matt Kemp, a shoe-in for the National League Most Valuable Player award, cashes in on his finest big league season. A 39 home run & 9 WAR opus that resulted in his team finishing a resounding third in the National League West. Kemp is, however, just one season removed from a very bad year in which he posted barely league-average offense (101 wRC+) and universally awfully defense in centerfield.

Which gives rise to the bigger issue: is this a good deal?

The degree to which Kemp struggles defensively shapes our view of of him and the value of his production. Fangraphs, powered by Ultimate Zone Rating, graded his defense as deplorably bad in 2010. The 25.7 runs below average submarine his ever-valuable WAR numbers, putting him barely above replacement level.

The other metrics aren’t nearly as harsh though they are universal in damning Kemp’s outfield defense. His arm is his strongest attribute but his range simply screams “right fielder” in the not-too-distant future. Is that what the Dodgers have in mind? What exactly are the Dodgers getting for their money?

Putting the questions about his defense aside for a moment, consider the downright nutty numbers Kemp just posted. 39 home runs and 171 wRC+ is nothing to sneeze at, no matter how bad his previous season. That 171 wRC+ is the second-highest by a centerfielder since the strike of 1994, behind only Josh Hamilton’s 2010.

It ranks ahead of anything Carlos Beltran or (not really a CF) Lance Berkman have mustered in their careers, higher than anything Ken Griffey JR posted in his storied career.

Can a player like Kemp continue to produce at this level? Consider a few cherry-picked comparisons below.

Source: FanGraphsMike Cameron, Jim Edmonds, Vernon Wells

In terms of career track, Kemp is ahead of these three players through his age 26 season. Unlike Edmonds and Cameron, he doesn’t derive the bulk of his value from his defense. (Note: comparing Kemp to Vernon Wells does the Dodgers outfielder a tremendous disservice. Sorry, Vern.) If Kemp moves to right field, does the contract look as worse?

If Kemp can keep posting seasons like his 2011 year, he can play wherever he wants. A .419 wOBA plays anywhere on the diamond, no matter how poor the outfield defense. Not many right fielders can claim adjusted numbers of Kemp’s size since the strike, offense-wacky era or otherwise. Even as a right fielder, Kemp can produce the type of offense expected of a corner outfielder while his defense figures to be league-average at worst when charged with covering less ground.

Assuming Kemp can repeat or even approach his 2011 numbers is a large assumption. His discipline took a major leap forward, walking at a career-high rate. Oddly, he swung at more pitches outside of the strike zone than ever before. How could that be? Simple. He started smashing inside pitches like never before.

Courtesy of ESPN Stats & Info

Will Kemp continue to see inside pitches on which to spin? Will the pressures of a big contract coupled with the ongoing adjustments of his opponents see his offense return to Earth? The Dodgers and Kemp both hope the answer to that is no. Kemp must remain an elite offensive producer for the bulk of his career to justify this incredible pay day.

2011 surely represents the peak of Kemp’s talent. Not to dimish it in any way, it is just career years happen. They happen quite often to 26 and 27 year-old ballplayers and not too often when they pass that age. Which isn’t to suggest Kemp will instantly turn to a pumpkin before our eyes. But expecting or demanding a near-1.00 OPS at Dodger Stadium simply isn’t realistic. But he must produce – and produce at levels he reached only one time previously in his career.

That is a big ask. The ballpark works against him but not something that is about to change. Kemp has a terrific health record and seems like a player the team like as their face. But a deal this long is scary for a player at the peak of his value.

The Dodgers are paying Kemp like a 54 WAR player for the life of the deal. Kemp has the skills as his humongous career year attests. His rare combination of power and speed earned him this pay day but when his legs slow and the in-play average sags (as in 2010), what kind of player will the Dodgers be paying $20 mil a season? The Dodgers are betting on Kemp playing as one of the game’s best hitters for a long, long time.

Railing against long-term, top dollar deals is nothing new. These deals not only end up crippling the teams, they can warp the perception of a player in the eyes of a fanbase. The pressure to live up to unrealistic expectations is hard enough, the hopes and dreams of a disgruntled fanbase can be quite the burden.