Josh Hamilton signed a surprise five year deal with the Los Angeles Angels worth $125 million dollars as they hope to out-hit their opponents on the heels of losing two important cogs from their rotation in Dan Haren and Zack Greinke. Forecasting a player’s career is one of the toughest things to do even when you have a guy who appears to be growing linearly at each level in the minors and then as a major leaguer. When you take one of the most unique cases ever like Hamilton, it gets a helluva lot harder, so I’m going to punt to a degree.

To guess how his body will age after what he put it through contains so much guesswork that it’s not even really worth it. Virtually every player has some sort of comparable within history to rely on or at least seek guidance from, but not Hamilton. Instead, let’s focus on the biggest change for Hamilton: his home ballpark. I think that will have a major effect on his production as he leaves one of the best ballparks in the game and enters a sneaky-tough one.

To the surprise of nobody, I hope, Hamilton does significantly better at the Ballpark in Arlington. Part of that is because virtually every player does better at home (unless you play in cavernous confines like Petco Park) and more importantly because TBIA is a very favorable park for hitters. It rated in favor of hitters across all major categories including 4^th in runs according to ESPN Park Factors. Baseball-Reference does composite park factors, one for batters and one for pitchers, where over 100 favors batters. Texas hasn’t been under 100 on either side of the ledger since 1994. In other words, it’s a hitter’s paradise.

And still a third outlet gets to the heart of how much Hamilton enjoyed his home park. Stat Corner shows park factors by batter handedness and they show Texas with a 117 home run factor for lefties. The same goes for doubles and triples while singles are still favorable at 103. Again, 100 is even so lefty batters get a 17 percent advantage on home runs in Texas. Just for a point of reference, we all know Yankee Stadium offers a very generous home run edge to lefties because we see it with our eyes every night, but the numbers back it up as well with a 146 factor. Keep in mind that these numbers from Stat Corner are three-year rolling averages.

So that is what he is leaving behind.

We saw in the figure above that he is still a mighty capable hitter elsewhere. If you average the home run and RBI totals over his average plate appearance count the last three years (582), he’s a 27-89 guy. So .294 average, 870 OPS, 27 home runs and 89 RBIs? That’s basically Andrew McCutchen the last three years. McCutchen’s 863 OPS is the closest match to Hamilton’s road numbers over the last three years. I used three years to approximate the plate appearances. Cutch had 2004 in that span.

Next closest was Evan Longoria, but I had to drop the plate appearance threshold to 1500. Longo has an 872 OPS in 1547 plate appearances as his 2011 and 2012 were injury-shortened. I’m not using these two as comps, rather using them to show what an 870 OPS guy looks like. The problem with using these two is their trajectories are a lot different than Hamilton. We can’t just expect Hamilton to put up a reasonable facsimile of his road work with the Angels because that doesn’t factor in his career trajectory or aging. Nor does it take into account the fact that he will be playing 81 games in Angels Stadium. That might actually be more important than anything his body does, at least in the short-term.

Going through our resources again, we see that ESPN had Angels Stadium as the 4^th-worst for runs scored and they didn’t register a favorable mark for hitters in any of the major categories, except for triples which isn’t exactly a major part of Hamilton’s game. In fact, they were 4^th-worst for hits in general, 6^th-worst for home runs, 8^th-worst for doubles, and 17^th-worst for triples. Baseball-Reference shows that they’ve gone from neutral/slightly pitcher’s park to heavy pitcher’s park just recently posting 92 batter and pitcher park factors each of the past two seasons.

Digging deeper with our third resource shows the real trouble. Or at least, potential trouble. Stat Corner given Angels Stadium a home run park factor of just 82 for left-handed batters! In other words, that park is suppressing lefty longballs 18 percent more than a “normal” park. Remember he was getting a 17 percent advantage in Arlington so this move constitutes a potential 35 percent dip in home run production for 81 of his games. His new ballpark also stifles double/triples to the tune of a 92 park factor while it is essentially neutral on singles with a 99 factor. Adding to chorus, Brian Cartwright, creator of Oliver, confirmed what we saw from Stat Corner.

How has Hamilton done in these confines through his career thus far? Glad you asked. Obviously with Rangers he has had plenty of exposure (his 166 PA there are his second-most in any park) to the ballpark, though it hasn’t exactly gone well on the whole. He has a .260/.325/.440 line with five home runs, 19 RBIs, 8 percent walk rate, and 17 percent strikeout rate in Anaheim. The story is bit different when you look at the five slices of the pie that make up these numbers, but does it tell us anything?

There is a small sample size alert in effect for the entire 166 plate appearances, so of course any one of the five slices receives the same alert, even louder to be honest. It is at least somewhat interesting that the composite is really brought down by a rough go in LA this past year. The Angels completely shut him down. To that point, he’d put together a .287/.367/.500 line in 128 plate appearances. Of course his big problem from 2012 at large rears its head here, too. His strikeout rate was enormous in Los Angeles last year just as it was with a career-worst 26 percent rate for the year. If that trend continues, his work in LA prior to 2012 won’t matter because the overwhelming swing-and-miss will continue to eat into his production.

I don’t necessarily expect him to crumble into a league average player because of his home park, but the impact should be significant even though he won’t be facing the Angels pitching anymore. He hasn’t really enjoyed success in any of the renowned pitcher’s parks in the American League where he has something of a sample (70+ plate appearances) except Cleveland.

I’ll reiterate again that these are all small samples. I’m not disclosing that so they can be ignored, just to point that I’m not putting an egregious amount of weight into them and you shouldn’t either as I’m sure many great players struggle in these parks. Conversely, they aren’t entirely meaningless either. In other words: the mean a lil’ somethin’. And let’s keep in mind that he has 18 games in the top two venues. So that’s 99 games in three venues where he hasn’t posted better than a 765 OPS for his career.

It should be noted that he will get a benefit of 18 games in the state of Texas to pad the road numbers we saw at the very beginning. He’s removing the LA ones and replacing them with nine in Arlington and nine in the home of the new AL West foe, Houston. He has been remarkably successful in Houston no doubt due to both the park and the fact that they haven’t exactly been awesome of late. Nor will they be in 2013, so that should continue. He has a .344/.400/.525 line with seven extra-base hits including a pair of home runs and nine RBIs in 70 plate appearances.

Where does all of this leave us?

Barring some serious changes from what we’ve seen to date, Hamilton’s production is a virtual lock to decrease and not just marginally.  As far as the contract goes, the baseball community has wins valued at about $5 million dollars per meaning Hamilton would have to be a five win player on average over the life of the contract to “earn” it. Of course there is other value to bringing in someone like Hamilton (listed lowest to highest, IMO) in terms of attendance, apparel sales, potential playoff earnings, etc… I honestly don’t believe I have the capability to calculate the exact impact for all of them, but I think you could reasonably slice a win per year ($5 million) off of “expectation” and it wouldn’t be completely out of bounds. In other words, I don’t think owner Arte Moreno and GM Jerry DiPoto signed this deal saying, “we absolutely, unequivocally think Hamilton will deliver 25+ wins during these five years, so we’ll go ahead and do this deal!” They are hoping for star-level production for the first two-three years resulting in no worse than some playoff appearances and ideally a title. If that occurs, they’ll consider the deal a success.

Slicing off the win from his expectation would then mean he has to be a 4.0 win player for five years, or net 20 wins however he wants to disperse them. Considering that his most favorable of the three win metrics (fWAR, rWAR, & WARP) was at Fangraphs and he was still “only” a 4.4 win player with an amazing year at the dish, I think he will be hard-pressed to fully “earn” the contract from a wins standpoint, at least in terms of how we calculate wins in the sabermetrics community. A lot of that seemingly low (when you consider his offensive output) win total from last year (btw, his rWAR was 3.4 & WARP was 3.9) is because he was a net negative in the field. Will he get better moving back to a corner outfield spot? Even if he does, will his bat stay on par with 2012 so that he’s then a 4-5 win player?

In a word: no. I just can’t see it happening. Hamilton is one of the most talented players in all of baseball so no one would lose their minds if he chased down a 1000 OPS again, but that would be an upset and fantasy folks should probably forget about the days of Hamilton’s MVP season (1044 OPS) and last year (930 OPS), instead focusing on his 2011 as a potential peak (882 OPS). The power output could be stunted to sub-30 levels, too. He hit 58 percent of his home runs in Arlington from the last years (that also happened to be 58 home runs as he hit exactly 100). He will struggle to keep that record going in Angels Stadium.

And again, all of this doesn’t even begin to try to factor his aging curve and his past troubles with drug addiction will play in his mid-30s. Hamilton is still a star-caliber player, but not necessarily superstar-caliber in his new digs so if your league doesn’t allow a discount for his switch in home ballparks, then bow out immediately. Tread cautiously.