Let's open the book of stats on this guy and get some facts about him. Because he's slow, I think I'd hit him behind Jason Bay, in the clean-up spot, unless Craig Wilson is all green, angry, and muscle-bound, ripping the ball like a healthy Hulk Man Jim Thome. Which he was, once upon a time, for half a season. My uneducated guess, the night of the trade, was that a healthy Casey will be something like a .300 / .370 / .480 hitter for the Pirates. Do the numbers support that expectation? In this post, I will take myself to school and look through his numbers. Jump to the end if you just want the conclusion.
A quick look at his 2005 splits sent me to his game log. Why? His righty/lefty splits are somewhat lopsided: he got about 200 PA vs. lefties and 350 PA vs. righties. That's a LOT of lefties for a left-hander to face. Usually the number is closer to one at-bat against a lefty for every three against a righty.
I went down this road awhile, but it's a dead end. Casey has no platoon split. He hits lefties and righties equally well, so there's no reason to think his 2005 numbers are skewed by that unusual parade of left-handed pitching before his eyes. Moving along ...
Staring the 2002-2004 averages in the eye, I see that .480 looks unrealistic as a starting point. The average of his 2005 numbers and his 2002-2004 numbers, .444, is probably a better starting point.
There two factors I would consider first when translating this .444 into black and gold. First, the effect of his home park. And second, the relationship between his health and his power. Since his health is bound up with his age, the two things have to be considered together. It's not at all clear to me if we should expect better or worse from Casey, going forward, because of recovery from health problems and aging. That will have to be another post.
Let's start with that ballpark in southern Ohio. It's new so the stats are slim. And it has a reputation for being a hitter's park. I've always chalked that up to the lousy Reds' pitching staff--something that would not benefit Sean Casey's home power numbers.
ESPN now provides this Park Factor page. It shows that the park was top-10 for homers, average for hits, average for doubles, and insanely below average for triples (he's not slow! no one triples in that park!). The 2004 numbers were the same. In '04 and '05, PNC Park played below average for homers, above average for hits and doubles, and average for triples. The 2004 Bill James handbook measured Great American as below average for left-handed batting average and above average for left-handed home-run hitting. The same authority measured PNC Park, in 2002-2004, as above average for left-handed batting average and below average for left-handed home-run hitting. In 2004 alone, it played above average for left-handed hitters in batting average and home-run hitting. As we all know, PNC plays more or less like a neutral park with two exceptions--right-handers lose home runs to Jason Bay in left-center, and some (but not all) left-handers have an easy time homering to right field.
That look into park factors suggests that Casey, a career .305 hitter, will hit for an even better average at PNC Park. He was fifth in the NL in batting average in 2005. He should, again, compete for a batting title in PNC in 2006. Despite the short porch in right, he may not hit more home runs. Great American was already padding his home runs numbers to about the same degree we might expect from PNC.
Average plays a role in slugging percentage. If Casey gets more hits, his OBP and SLG stand to gain from that. How much? Let's say not much, but let's remember to add a few points to his OPS at the end.
Now that I've looked at the park effect in a general way, it makes sense to look at it in a specific way. In other words, how much did Sean Casey like hitting in Great American Ballpark? He surely spent many days wishing he was hitting off his own team's pitchers, but given the park's reputation as a launching pad, we'd guess he liked it, right?
Well, that would be wrong. In 2005, the Mayor hit .293 / .352 / .395 at home. And he hit .330 / .389 / .451 on the road. That's 750 OPS at home, 840 on the road. How was this guy a fan favorite?
His 2002-2004 splits are even more Cincinnati-hating. I like him more and more to learn that. He hit for a 900 OPS on the road and a 750 OPS at home. That's amazing. But, it stands to reason. If you lived in Cincinnati, wouldn't you hate it? That is one ugly lice- and interstate-infested city.
Sean Casey hit .341 / .397 / .504 outside of Cincinnati between 2002 and 2004. He hit .278 / .337 / .408 in Cincinnati. One of us! One of us! One of us!
The 900 OPS, preferably with 380+ OBP, is the threshold for me between good hitter and Damn Good Hitter. I especially get drooling when I see a high OPS that's 45% OBP. That's good stuff people.
Unfortunately, since the Reds are in our division, Sean Casey will play a lot of games in his 750 OPS shoes. Sixteen, I think. The good news is that we can expect to see more of Casey's road numbers.
We all expect to get something like the best of him here in Pittsburgh. After all, we all know he has murdered Pirate pitching. It's Pirate pitching, some will say, so his .378 / .459 / .581 numbers in PNC Park for 2002-2004 don't mean much. I say they're wrong. Our pitching has long been average; it's our hitting that has flat-out sucked the last five years.
Instead of playing 81 games in the GAB, Casey will play what, 16 games there. If we average his three-year to 2004 and 2005 numbers, we get 750 OPS at the GAB, 870 elsewhere. If we weight them as a Pirate, we get ((750*16)+(870*(162-16)))/162 or 858.
So I'm now expecting he'll manage an 860 OPS (I'll add a conservative two points for the good effect PNC will have on his batting average and the non-effect it will probably have on his home-run hitting [see above]).
If it's a typical Sean Casey OPS distribution - his career numbers are .305 / .371 / .462 - we're looking at something like .325 / .380 / .460 as a Pirate. I will take that and I will like that.
And that's without weighting PNC heavier than all the other road stadiums Casey visited as a Red. Let's not overstate his love of PNC; he's only played about sixty games here over the last four years and maybe they fell in unusually healthy places.
... Vlad uncovers this great Primer link for more park factors.
... And all hail Tom Veil making some of these same arguments in previous comment threads. If I had thicker skin, I'd read all them comment threads more carefully.
... And note our Official non-patented Honest Wagner KHALIFA projections consider age and health history, so this current projection is merely a working one.