Naturally, this is an absolute art, not a science. If we'd been doing this exercise five years ago, and someone would have said the previous year's eighth-round pick could end up being the most valuable player in team history... So, it's quite possible that, lurking somewhere in the depths of our farm system is the next Paul Goldschmidt-esque player. I'm not even going to try and forecast that, so this list is limited to those who have made the major leagues, and spent sufficient time there I can make a semi-decent effort at predicting overall production. So, no Jake Lamb or Archie Bradley.
There are a few fringe candidates who might have a shot at cracking the top ten, but that obviously would depend on how their careers progress going forward, Adam Eaton (age 26, 6.2 WAR) is a possibility, though so far, his 2015 has been a shadow of his success with the White Sox last year. Wade Miley has 6.5 WAR, but at 28, is a couple of years older. Brett Anderson (age 27, 7.1 WAR) also has a shot, though health is a big question-mark for him; from 2010-2014, he has never reached even twenty starts in a season, and averaged only half that.
Of course, the all-time leader to this point is someone drafted, not once, but twice, by the Diamondbacks, yet who never played a day for them, even down on the farm. Four-time All Star Ian Kinsler, a local kid born and brought up in Tucson, was drafted out of high school by Arizona in the 29th round of the 2000 draft and didn't sign. Undaunted, the team picked him again the following June, this time in the 26th round out of Central Arizona College. He didn't sign there, either. Finally, in 2003, he signed for the Texas Rangers in the 17th round. He put up over 35 WAR for them, before being dealt to Detroit for Prince Fielder. Total WAR: 42.9, and still counting...
10. Stephen Drew. 1st round (#15) 2004. 15.6 WAR
Drew's stay in New York is not going well. After 92 games, his line for the Yankees is 154 /.222/.287. The resulting .509 OPS ranks him 328th of 331 of non-pitchers with 300+ PA in franchise history. The media is smelling blood, e.g. yesterday's headline in the New York Post: The $240 million fall from Robinson Cano to Stephen Drew. Ouch. But from 2008-10, he was worth almost ten wins; there were only half a dozen more valuable shortstops over that time. Having just turned 32, his career may not be at an end, and he could still move up a slot or two. However, having been worth -0.9 WAR with the Yankees, he'd first need to stop sliding back.
9. Lyle Overbay. 18th round (#538) 1999, 16.9 WAR
I was a little surprised to see how highly Overbay ranked, but he had longevity on his side, playing 14 seasons before calling it quits at the end of last year. That included two spells with the D-backs, but his most productive years were out of the NL - and indeed, out of the country, playing with Toronto, putting up 12.3 WAR from 2006-10. Maybe that's why I didn't notice! However, despite his lengthy career, his only post-season experience was in the 2011 NLDS for Arizona against Milwaukee, going 0-for-4. Never an All-Star, never got an MVP vote, but with career earnings of over $36 million, he did well enough, I'd say.
8. Dan Uggla. 11th round (#338) 2001. 18.0 WAR
Or "Byrnes's Folly," as he should perhaps be known. Just two months after becoming GM, Josh Byrnes left Uggla unprotected for the Rule 5 draft, and the Marlins swooped in. Uggla didn't just stick on their roster, he played in the 2006 All-Star Game at PNC Park, and finished third in Rookie of the Year voting, hitting 27 homers. From 2006-11 - the years of team control we could have had - he went deep 190 times, 45 more than the next second baseman, and among the top ten in all baseball. Has fallen off a cliff lately, being worth -2.4 WAR since the start of 2012, but for quite some time, he was a scary man for pitchers to face.
7. Brad Penny. 5th round (#155), 1996, 19.2 WAR
Like Uggla, a player we drafted, who never played for the Diamondbacks. Penny was selected before the team had even played a game, and was part of a trade with the Marlins for Matt Mantei, not long after his 21st birthday, while still in Double-A. An All-Star alongside Uggla in 2006, while with the Dodgers, he repeated the feat the following season, in what was his best year, going 16-4 with a 3.03 ERA and finishing third in the Cy Young voting. He was unable to capture that form again, and thereafter has been worth -1.3 WAR. Still rattling around, twirling away in Triple-A for the White Sox affiliate, but to all intents and purposes, the 37-year-old is done.
6. Trevor Bauer, 1st round (#3), 2011. 2.1 WAR
This is probably the hardest on on the list to project, because Bauer is still so young (24), and though this is his fourth year in the big leagues, we have little more than a season of data to go on. 2.1 WAR over 44 starts isn't great, but since the start of 2014, in basically a year's worth of starts (36), he has been worth 3.2 WAR. Given his age, there would seem to be some upside, but the old adage, "There's no such thing as a pitching prospect," likely extends to all pitchers under 25. Or even older: just ask Jarrod Parker. So, Bauer could end up pitching for another decade-plus, and going past all other contender. Or not.
5. A.J. Pollock. 1st round (#17) 2009. 9.6 WAR
The more I see of Pollock, the more I like him. I think the injury which sucked out the heart of his 2014 campaign also took him off my radar, but he's making up for lost time know: having him on my fantasy team perhaps helps too! A.J. has been impressive in just about every aspect of his game, with his walks, stolen-bases and home-runs all less than a handful shy of last year's totals, after the first couple of months. 48 games = 2.4 WAR. He's clearly our best outfielder, and should be in the starting line-up. Every. Single. Day. He will hit arbitration next year; I'd be looking to buy that out, sooner rather than later. With over a thousand PA, we know his value.
4. Brandon Webb. 8th round (#249) 2000, 31.4 WAR
What might have been? It's safe to say that the injury issue ended Webb's career, well before its time, and if not for this, he would likely be further up the list than he is. But how far? From ages 24-29, Webb put up 33.5 WAR: here's the list of recent pitchers to have put up WAR of between 30-40 over that same period in their carers, so we can perhaps see what might have been, had health not curtailed Webb, close to his peak. For instance, they include Roy Oswalt: he was worth 32.2 WAR from ages 24-29, and ended his career a hair shy of fifty WAR. Or Roy Halladay: 31.6 WAR, leading to more than 65 for his career. I'll stop now. I'm making myself sad.
3. Justin Upton. 1st round (#1) 2005. 22.3 WAR
This and the next pick were already discussed a fair bit, when we looked at the team's first-round picks, a couple of weeks ago. But it has been impressive how Upton has performed this season, with an OPS+ of 158 to date, which is the highest of his career. Of course, we're all too familiar with his hot streaks and slumps, so I wouldn't quite go penciling him in as an MVP. But with free-agency looming this winter for Upton, it's going to be very interesting to see what kind of offers there will be for him, especially considering he will be hitting the market at age 28, in the prime of his career. Six years, $150 million? Might not be too much of an exaggeration, if he keeps hitting like he has.
2. Max Scherzer. 1st round (#11), 2006. 27.4 WAR
No such worries for Scherzer, who has certainly started off his time in Washington, as if he means to justify that $210 million contract. A long way to go though: he'll be 37 when the contract finished, and 44 by the time the Nationals finish paying off the deferred aspect of Max's salary. With no trips to the DL since becoming a full-time major-leaguer at the start of 2009, his health has been great so far. But Bronson Arroyo - and, indeed, Webb - would like to remind you, "so far" are the operative words in that sentence. Still, with so much WAR already in the bank, he won't be dropping out of the top three anytime soon.
1. Paul Goldschmidt. 8th round (#246) 2010, 18.8 WAR
Holy mother, Paul has been good. Only one player in D-backs history has had an OPS of 1.000 or better over the first half: Luis Gonzalez, who did it in 1999 and 2001, much better environments for hitting. Coming in to last night's game, #50 on the season, Goldie had an OPS of 1.143. He has been worth 3.5 WAR already this year, and we're not even one-third of the way through it. There is absolutely no reason think he won't keep churning out the production for the foreseeable future: playing first, he won't be crashing into outfield walls, and even if he loses a step or two, it won't hurt his value much. I think he'll have passed Scherzer by the end of 2019. Hopefully, still as a Diamondback.