Aaron Hill Extension: The Possible Downside?

Coming out strongly against the extension was Matthew Pouliot of NBC Sports, who took a look at players with roughly similar career bWAR as Hill's to age 30, and concluded:

Of the 11 players here to play in the last 50 years... only [Ray] Durham maintained his previous level of production at ages 32-34. Most of the rest weren’t useful at all. That’s the tendency with second basemen: once they stop being quality regulars, their lack of versatility prevents them from contributing even as part-timers. Taken altogether, the average player here produced 3.3 WAR from ages 32-34. The Diamondbacks are expecting much more than that from Hill after guaranteeing him $11.67 million per year. History suggests they’ll almost surely end up disappointed.

While I see the underlying principal, I have some issues with the specific methodology, in particular the use of career WAR: that number tends to depend too much on when a player joins the majors. Hill didn't start playing until the age of 23, three years later than, say, Luis Castillo, one of the comparables Pouliot uses. I think a better method is to do what we did in our earlier piece: take the last four years and see what we come up with for numbers around Hill. Here's the chart for that: those who put up between 10 and 13 bWAR over their 27-30 campaigns since 1961, which more or less sandwiches Hill's 11.3 over that time. nWAR is what they did from ages 31-34.

Reynolds, Offerman and Sanchez didn't actually have an age 34 season, for one reason or another, so their pWAR is in italics. If we exclude them, the other ten, show an almost even split between those who played well (Franco, Randolph, Lopes), those who played acceptably (Hudson, Garner, Ellis) and those who were busts (Herr, Mazeroski, Beckett and Kennedy). The average production of those ten was eight WAR, over the four year period during which Arizona will be playing Hill $40 million. However, it is true that in some cases, it was very front-loaded. O-Dawg, for instance, put up 3.9 bWAR at age 31, then only 3.1 over the next three years combined.

A couple of other points to ponder. One would presume that medical technology is advancing, and so players would now be aging better than they did in the 60's and 70's - and I'm talking about legitimately, rather than patronizing certain Florida clinics! Yet, of the five best-aging players, only Mark Ellis occurred post-1990, and his numbers to age 30 came despite missing the entire 2004 season due to a torn labrum in his shoulder (after a collision with fleeting Diamondback, Bobby Crosby). Shoewizard also came up with some well-considered thoughts on Hill and aging, in the comments on the previous post:

Regression aside, Hill’s extreme pull tendency is what bothers me the most when it comes to committing to him long term. He already struggles badly in LATE AND CLOSE and Innings 7 thru 9. League averages dip in those situations of course….harder throwing relievers at the back of bullpens suppress offense. But it’s my opinion that Hill is more vulnerable to that because he is such a dead pull hitter. And as he ages, and loses just a tick of ability to turn on the hard stuff, he’s going to start cheating more, and then will really have a tough time, unless he adapts and starts hitting the ball the other way much much more than he has his entire career.

Twitter had an interesting discussion between Brad Ziegler and Nick Piecoro, Ziegler suggesting, in response to the NBC Sports piece, that post-concussion syndrome caused Hill's struggles. Piecoro seemed dubious, pointing out neither Hill nor John McDonald had brought it up, despite being asked, on multiple occasions, what they felt was the cause. Brad replied, "When have you ever heard Aaron Hill make an excuse for anything? Ask guys who played against him and they always noted it." It seems unusual to hear a team-mate going public like this - especially when, as recorded by 'Charmer, Hill still doesn't have an answer for his improvement since coming here.