I took Rodriguez's top 20 PECOTA-comparable players and averaged their performances over each remaining season of their careers. Actually, the process was a little more complicated than that (each comparable's performance was adjusted for his park and league context, as well as his previous track record, and we had to make an accommodation for guys like Manny Ramirez who made A-Rod's comparables list but have yet to conclude their own careers). But the basic idea is simple: Comparables like Frank Robinson, who aged well, have a favorable effect on Rodriguez's forecast, and players like Caminini [sic] just the opposite one.And here are the projections (I've added A-Rod's two previous seasons in white):
There are three glaring problems to me.
- Silver predicts a near-linear decline, with each total being 2-6HR lower than the preceding year. This, of course, is the result you are going to get when you take his "top 20 PETCOA-comparable players" like Silver did. If you take any 20 players and average their careers, the total number of home runs is almost always going to decline with age. Increase the sample size and it will always decline. The only problem is, over that ten year period it is extremely unlikely that any individual player is going to have that consistent of a downward slide. I will bet anyone reading $100 that this doesn't happen to A-Rod. First one to take the bet in the comments is on, we can iron out the details later.
- A-Rod is going to be able to DH at some point. Common knowledge would suggest that playing regularly in the field puts wear and tear on a body, draining energy in individual games and effectively shortening careers. Many of his comparables didn't have that luxury and were driven out of the league because they were no longer well-rounded players, not just because they could no longer be effective at the plate and hit home runs.
- The problem with being on pace to be the greatest home run hitter of all time is that you aren't going to have too many people similar to you.
Here are Alex's 20 comparables (and their career HR totals):
- Sammy Sosa (609)
- Bobby Grich (224)
- Dave Winfield (465)
- Ken Caminiti (239)
- Ryne Sandberg (282)
- Frank Robinson (586)
- Dwight Evans (385)
- Jeff Bagwell (449)
- George Brett (317)
- Reggie Jackson (563)
- Hank Aaron (755)
- Greg Luzinski (307)
- Albert Belle (381)
- Reggie Smith (314)
- Manny Ramirez (527, Inc.)
- Carlos Delgado (469, Inc.)
- Dick Allen (351)
- Doug DeCinces (237)
- Larry Walker (383)
- Tony Perez (379)
Granted, PETCOA's comparables are based on a ton of things besides home runs, but the problem with this list is that A-Rod already has more HRs than 16 of the guys on it. He has twice as many as his second and fourth closest matches and his career isn't over. I know Nate is going to lean on his own projection system for a variety of reasons, but it would probably have made more sense to look at the top 20 career HR leaders. We are, after all, trying to predict how many home runs he is going to hit and he's already #12 on the list.
I realize that the most reliable way to predict future outcomes is by analyzing past events. However, the flaw in using this methodology is that it becomes impossible to predict when someone will do unprecedented things. Simply put, how is analyzing 20 guys, none of whom is the career home run leader, ever going to result in the simulation predicting A-Rod will break the all-time record?Look what happens when you line up A-Rod's projections with Hammerin' Hank's:
For one thing, last year, A-Rod played in only 138 games. If he played 156 games, he was on pace for almost exactly 43 HRs, right in line with a 32 year old Aaron.
Where the big differentials come in, are from ages 35-39. As A-Rod enters his steady plunge into oblivion (98HR, 19.6/year), Hank checks in with 203 round-trippers (40.6 per year) including the highest single season total of his career (47 at age 37).
There's no guarantee that A-Rod will hit even one more home run. He could get struck by lightning tomorrow. I just don't think that Alex is going to take the field on a consistent basis and gradually slide off into oblivion like PETCOA projects. The truly eye opening part of Silver's projection is that he'll would still only be 33 HRs away from the all-time record even if he is as bad as the simulation predicts.
Before you leave a comment telling me how much of a moron I am, I've posted my own projections here.