Castro's on the block...

Apparently the Chicago Cubs are in full-blow rebuilding mode. Celebrity GM Theo Epstein has come out and said that he'd be willing to hear offers for every Cub except pitcher Jeff Samardzija. This makes perfect sense since Theo wants to enter the Cubs into a company flag football league and he's banking on Samardzija to be the team's star. Go Irish! No, honestly I don't understand why he's the "untouchable" North Sider. Don't get me wrong, Samardzija is a good young pitcher. At the same time, he's not that good (4.04 career ERA) and he's not that young (27). Anyway, that's not really the point. Even though I'm pretty surprised about who Theo is protecting, I'm more interested in looking at one of the guys that is apparently now on the market. Starlin Castro. Castro is a good young player. He led the Senior Circuit in hits last season as a fresh-faced 21 year old. He's also a shortstop. At first glance, he looks like he'd be a perfect fit for a Pirates team that has been disastrous at the plate and has given 151 plate appearances to Clint Barmes. What I'd like to do is see just how much a young player like Castro would cost and try to figure out whether he'd be a good target for the Pirates.

So where to start? I guess the first question that we have to answer is just how good Starlin Castro really is. He's pretty damn good, actually. As a 20-year old rookie in 2010, Castro put up 1.4 rWAR and 2.2 f WAR in just 125 games. He followed that up with an impressive sophomore campaign, posting a 3 rWAR and a 3.4 fWAR last season. So far this season, he's been worth 2.2 rWAR and 1.7 fWAR. Over a full season that projects to a whopping 7.1 rWAR and 5.5 fWAR. However, since these numbers are partial season numbers, it's important to look at just how Castro is putting up his big numbers this year. Offensively, there's not much different between the 2012 version of Starlin Castro and the 2011 version. His wOBA this season is actually down slightly from .338 to .337. The big change, though, has been with the glove. Last season, Castro was a poor defensive SS with a UZR of -8.7. So far this season, his UZR/150 (or his projected number over roughly a full season) is 11.6. This means that over a full season, Castro's 2012 defense is worth about 2 wins more than it was in 2011. Did Castro really improve his defense that much over the offseason? Probably not. UZR simply takes a while to normalize and a third of a season is just not a representative sample size. He might have improved somewhat but he still looks like an inconsistent defender at short.

So what do we do with all of those numbers? Because of his age, I don't think it's out of the question to believe that Castro will improve. Also, since Epstein doesn't have to deal Castro, I doubt he'd accept a trade unless the other team were paying for Castro based on a best case scenario (or close to it). By splitting Castro's 2011 fWAR and his projected 2012 fWAR, we come up with 4.5 WAR which seems like a reasonable, albeit somewhat optimistic projection. Just for reference, in the last 50 years, there have only been 10 SS to average 4.5 WAR from their 4th through their 7th years; A-Rod, Ripken, Jeter, Jim Fregosi, Rico Petrocelli, Larkin, Nomar, Furcal, Tulo and Trammell. It's just not easy to do. For the sake of argument, though, let's assume that he could get it done. Again, since Epstein is in no rush to deal Castro, I wouldn't be surprised that he'd be looking for a trade partner that thinks this highly of Castro. Those 18 wins, combined with the 2.8 WAR that Castro could still provide this year means he'll provide 20.8 WAR after being traded. At $4.5M per marginal win, Castro would provide roughly $93.6M in value over the next 4+ years.

Castro is under control until after the 2016 season but he is not under contract, so his salary is a bit of a question mark. Over the rest of this season, he's due about $400K, but he'll be a Super-2 which means he'll receive arbitration for the next four seasons. If we assume that he gets paid according to the rough 20/40/60/80 arbitration rate, that means Castro will earn approximately $40.5M during the arbitration process meaning he'll be paid about $40.9M before hitting free agency. This would give Castro a "surplus value" of $52.7M.

So what kind of package would the Pirates have to put together in order to land Castro? A big honkin' one. The Pirates' two best prospect are, by all accounts, Gerrit Cole and Jameson Taillon. Most midseason reports have suggested that both players are in the top-10 overall prospects. This is due to a combination of their impressive performances, and the graduation of top prospects like Bryce Harper and Mike Trout (who will be better than Harper, write it down). I've fudged the numbers a little bit with Victor Wang's research to reflect a statistical anomaly that actually values pitching prospects in the 11-25 range more than guys in the top-10. Quite simply, I just mirrored the jump that we see in the value of top-10 hitting prospects. This means that top-10 pitching prospects would be worth $23.1M each. Hitting prospects, because they are safer (TINSTAAPP) have greater trade value. Starling Marte, as a 26-50 hitting prospect would be worth $23.4M. Obviously valuing Marte above Cole and Taillon is debatable, but I'm just going off the numbers, so don't shoot the messenger. Since Cole can't actually be included in a trade yet, let's say the Pirates built a package around Marte and Taillon. Those two would have a total trade value of $46.5M which means the Bucs would have to come up with a cherry for that sundae. To make up the $6.2M that they are short, they'd have to throw in a B-grade hitter and a C-grade hitter under 22. That would be somebody like Robbie Grossman and Mel Rojas Jr. So there's your package. Castro for Taillon, Marte, Grossman and Rojas. Would you do it? I certainly wouldn't.

Don't get me wrong, Castro's a very good young player, but the walk rate (down to a minuscule 2.3% this year) and the BAbip (Castro has the 9th highest BAbip out of any player during his first three seasons in the last five decades). A detailed analysis of his swing data shows that pitchers are starting to adjust to his swing-happy approach and that doesn't bode well for his sustaining this pace. That's a question for another day, though.