There has been somewhat of a trend the past few weeks with players moving from one park extreme to another through trades and signings, so this week we will focus on how these contextual changes will affect their performance and fantasy value. Dan Haren was one of the top pitchers in the American League last year, and now he is moving to the National League to pitch for the Arizona Diamondbacks. Haren isn’t in any danger of pitching poorly after the switch, but there are a few things to consider when attempting to assess his draft or auction value.

First off, Oakland has more of a pitcher-friendly park than Arizona, especially against right-handers. Haren pitches effectively against both (.230/.289/.374 against LHB, .264/.293/.417 against RHB) but it’s important to note that the difference in the home runs allowed for the two stadiums is massive. Chase Field is one of the best parks in either league for right-handers to hit homers, and it’s arguably the leading locale in the league for left-handers looking to put one over the wall. Oakland, on the other hand, minimizes the impact of homers from both sides of the plate by a significant amount.

Part of Haren’s success this past season was due to his giving up fewer homers per fly ball, which could now change in 2008. Also keep in mind that Haren’s fly-ball percentage has moved from 32 to 36 to 38 percent in each of the past three seasons; that’s more opportunities for balls to fly over the wall. Taking a look at his QERAs over that same time frame, we see that Haren has been essentially the same pitcher for at least the past two years: 4.02, 3.71, and 3.72. Considering he will more than likely give up additional homers with the change in parks, you can expect Haren to be somewhere within that range once again, with an ERA that more closely reflects that figure than that of his 2007. That should encourage people to leave Haren on the boards at draft time until after the frontline starters have been selected.

First thing is first with Aaron Rowand‘s 2007 performance: if not for his .348 BABIP, he would not have hit over .300, and he would not have delivered a .309/.374/.515 line. In light of his 19.8 liner rate, all things being equal he should have been around .318 for his BABIP, meaning that his season line should have been somewhere around .279/.344/.485. As far as what may hurt his future performance, Rowand hit 27 homers last year, with 17 of those coming at home. Citizen’s Bank Park is one of friendliest places in the league for homers from either side of the plate, and the right-handed Rowand took advantage of that by whacking homers over the park’s short wall in left:

The hit chart from shows that Rowand can hit some long balls, but for the most part he puts them right over that short wall in left. The walls are a bit further back at AT&T Park in San Francisco, Rowand’s new home: it’s 339 out to the left field corner, and the outfield has fewer odd angles that can turn a fly ball into a homer. The wind is also different than in Philly. These factors should combine to negatively impact Rowand’s performance. Whereas Citizen’s Bank was among the top parks for homers, AT&T is one of the worst for hitters from either side of the plate.

Considering Rowand doesn’t steal often, doesn’t sport a high OBP-he’s been well below-average in that category as often as he has been at or above it-and won’t offer much power out west, it would be insanity to pick him up before your draft is at least halfway over, and that’s if you’re in a deep league or one that requires center fielders. It’s best to put him into the “wait and see” category than it is to waste too lofty of a pick on him.

The Astros dealt for Miguel Tejada to boost their lineup’s production, though they may be a few years late on that note considering the questions surrounding Tejada’s actual age and his recent dip in both productivity at the plate and mobility in the field. Outside of that questionable call-which Joe Sheehan covered last week-we’re left to wonder what Tejada’s National League production is going to look like.

Minute Maid Park has a reputation as a hitter’s haven, but the past few years it has played more neutral than anything. Right-handers see an increase in home runs, and both sides of the plate enjoy a boost in triples thanks to the deliberately awkward angles designed into the outfield wall, but other than that it is a neutral park that leans more towards pitching than offense. Orioles Park at Camden Yards is also a neutral park, but it offers about the same advantage for righties that Minute Maid does, which does not bode well for Tejada’s slipping power.

If you are looking for a boost in his RBI and Runs, you might have more luck there. The Astros and Orioles lineups posted nearly identical EqAs in 2007 (.257 and .256, respectively) but the Astros have shed some of their dead weight this winter. Adam Everett‘s .209 EqA is no more, which is great for your fantasy team as long as you don’t own any of Houston’s pitchers as well. Craig Biggio and his .229 EqA are sitting at home waiting for his turn at the Hall of Fame, Chris Burke‘s disappointing .235 EqA is now the property of the Diamondbacks, and Jason Lane (.211) is also missing. Of course, they are now also without Luke Scott‘s .286 and are still in possession of Brad Ausmus, but losing the above names is a start as far as something better. Houston’s offense will still be in the range of average, but Tejada should be surrounded by Lance Berkman, Hunter Pence, and Carlos Lee, which should increase team-dependent numbers like RBI somewhat.

Lastly, we have Jim Edmonds, who is going from a park that has played very pitcher-friendly since opening over to the most severe pitcher’s park in the majors in Petco. Edmonds is a huge question mark all the way around thanks to recent poor performances and the nature of his new home park, though as far as homers are concerned, the difference between his new and old locales isn’t that great. Edmonds managed just .252/.325/.403 last season in limited duty, and his .151 ISO was his lowest output since 1994 with the Angels, when he hit like a middle infielder. Nothing in his batted-ball data has changed as far as distribution goes-45 percent of his batted balls are fly balls and roughly 20 percent are line drives-but he has seen his BABIP drop from some of the obscenely great years he put up in the past to a more league-average output. Edmonds has also seen his HR/FB fall from 19.1 to 16.8 to 9.1 percent the past three seasons.

A seemingly endless list of injuries and aging are to blame for many of his problems. If anything is to revitalize Edmonds’ numbers at all, it will be the platoon the Padres will more than likely place him in. Edmonds hit .268/.336/.419 against right-handed pitchers last year, which isn’t impressive but is still well above his performance versus southpaws. As recently as 2006 he hit .295/.404/.543 against the normal-handed, so as long as his bat has not slowed too much he may be able to regain some portion of that to put up league average numbers. Since the Padres have Scott Hairston and his power sitting around, they should be able to pair these two up somehow, though they will need to keep Hairston’s glove out of the expansive Petco center field. Hairston has not hit lefties much during his time in the majors, but the sample is still very small, and he is a right-handed batter. He also managed to hit .287/.337/.644 in limited duty once the Padres acquired him, so they should at least try him out to see if he can avoid costing them too many runs at the plate over the course of a year.

As far as draft time is concerned, you shouldn’t bother with these two players. It’s a pairing you will want to keep your eyes on as the winter and season progress though, because a healthy Edmonds combined with Hairston’s potential power-I say potential more because we need to see it happen in the majors-could make for a useful addition to your team at midseason.