Expect his value to decline, maybe by even more than you expect
Josh Hamilton has been excellent in the past, but signing with the Angels is very likely to ding his fantasy value. In his career, Hamilton has hit .315/.373/.592 in Rangers Ballpark in Arlington, and is at .305/.363/.549 overall while playing with Texas. It's not a gigantic discrepancy, but it's something, especially if you're choosing between Hamilton and other fantasy players who might end up being better options.
Part of why Hamilton has been better in Texas is because of the park. It's a hitter's park for both right-handed and left-handed hitters -- for homers, specifically, left-handed batters like Hamilton have averaged a 17 percent boost. Doubles and triples get the same boost, so while Hamilton's batting average on balls in play hasn't jumped up significantly in Arlington, his Isolated Power has seen a significant jump in home games.
In a neutral environment, you'd likely see Hamilton's stats dip closer to his road numbers -- a still-impressive .292/.354/.504. With Angels Stadiun in Anaheim, though, there could be more significant issues: that park reduces homer power from left-handed batters to a degree equal to Arlington's boosting of them. We've already seen him hit worse in that environment in 166 career plate appearances there, to the tune of .260/.325/.440. That being said, it's a small sample, so there's no need to jump off the Hamilton bandwagon based on 38 games worth of playing time. His power does play everywhere -- his average homer distance in 2012 was 416 feet, and all but a handful of them would have been out in most parks -- and since he has tremendous power to right-center, where the walls aren't quite as deep in Anaheim, the changes might not be anywhere near as significant as some fear.
There are other concerns worth nothing, though. Hamilton's second half was nowhere near as good in 2012, with the outfielder hitting .245/.322/.487 from June 1 onward, with strikeouts 29 percent of the time. That's a 10 percentage point jump from both his career rates and where he was prior. This was covered in more detail just a few weeks ago, when the Hamilton market was at its busiest:
Hamilton swung out of the zone more frequently, and he swung in the zone a little more often, but more swings simply resulted in missing with more regularity: his contact rate dropped from around a career rate hovering in the mid-70s to just 65 percent in 2012. He missed more often in the zone, but the more significant occurrence were his swings out of the strike zone. PITCHf/x says Hamilton swung and missed on more than half of the pitches he took a hack at outside of the strike zone. In past years, he chose his moments more wisely, and dropped below 61 percent just once in his entire career. This past season represented a serious change, and if you consider how he was in line with career norms for the first two months and 200-plus plate appearances, the drop during his struggles is likely even larger than the full-season data suggests.
The issues can be seen in his deeper counts. With two strikes on him, Hamilton punched out 51 percent of the time. The rest of the American League struck out in that situation just 39 percent of the time -- high, as you would expect given they are one strike away from heading back to the dugout, but nowhere near as lofty as Hamilton. He was still better-than-average overall in this situation, thanks to 11 two-strike homers on the season, but if his new approach to plate discipline holds, that can be limited in the future by going out of the zone more often and forcing him to chase. That's not a given, as Hamilton could adjust back, but it's something to consider: skills do erode with time, after all, and sometimes chasing like that can be a sign of things to come.
If his bat speed starts to decline, and he continues to swing out of the zone, the combination of his talent slipping and the move to Anaheim is going to be problematic for his fantasy value. There's reason to believe, though, that a lot of Hamilton's issue in 2012 had to do with failure to adjust -- pitchers began to throw the ball out of the zone more often, because throwing it in the zone was a dangerous proposition during the two months in which Hamilton was going deep seemingly every other time up to bat. Hamilton began to chase, though, and pitchers continued to go out of the zone, because why wouldn't they? It was a low-risk way to attack a hitter only to happy to comply.
If Hamilton gets his head on straight for 2013 and stop swinging so often out of the zone, and can get back to where he was not even during the first two months of the season, but just his career levels, then all fantasy owners (and the Angels) will have to contend with is his new park. It's a big risk, so maybe take your foot off the pedal in the Hamilton chase a bit, but there's still a lot of upside here if you're forced to draft him when other equivalent options no longer remain on the board.