Should the Sox Try For Santana?

I opened up Boston.com this morning to see what was going on in hot stove land, and came across this piece by Eric Wilbur on the relative value of putting Johan Santana or Dan Haren in red stirrups for 2008, who it would cost the Sox to make such a mega deal happen, and whether or not the overall deal would make sense for both our 2008 championship aspirations and the future of the club. Wilbur made an interesting point: he said that if the A's are looking to shop Haren - something that's still only in rumor mode at this date - he'd be a much better choice than Santana, and I agree. Here's why:

• Santana's numbers at Fenway are pretty ugly: 29 base runners and 12 earned runs in about 16 innings. Haren's Fenway numbers in the same number of innings are better (26 base runners and 8 earned runs), and he's two years younger. If we're going to lose a year having a pitcher adapt to winning at Fenway, I'd prefer it'd be from the guy who's got a head start and the younger age. On a related note, if the Yankees grab Santana, his history in Fenway means he won't be an automatic Sox killer.
  
  
• After his monster year in 2004, Santana's ERA+ fell about 25 points in 2005, then took another 30 point drop in 2007, leading to (among other things) a failure to anchor the pitching staff on my fantasy team. More importantly, although he's had his famous second-half resurgence every year since 2004, the quality of those resurgences is slipping: OBP against, for example, was nearly equal in both halves of 2006, and higher in the second of 2007, where it had been much lower in the second halves of 2004 and 2005. Might this be part of a trend?
  
  
• Santana will cost a whole lot of money to keep - he's coming into the end of his contract, and Wilbur has his rumored asking price at $25 million a year. A contract year performance would support that kind of money, but if Santana's entering a period of decline, he won't be worth $25 million in 2009. Haren, meanwhile, is a paltry (by comparison) $5.4 million for the next three years; plenty of time for him to prove he can be another dominating starter at Fenway without nearly as much monetary risk.
  
  
• Haren's numbers have been trending up since he became a full-time starter in 2005, and garnered an ERA+ of 137 (his highest yet) in 2007. He hasn't reached Santana's godly levels, but he's definitely getting much better as he gets older.
  

Now, assuming such a deal might actually take place (and the great news for us fans is that it doesn't have to happen for us to feel secure about next year's start), who would be the logical trade bait? I say Coco and Lester. Coco's the obvious choice - he's never lived up to his promise in Boston, and Ellsbury has "rising star" written all over him in permanent black marker - while Boston's surfeit of pitching makes Lester the more attractive option (over Buchholz) to deal away; his peripherals are trending in the right direction (lower WHIP, higher strikeouts per inning), and he's had more time to prove himself at the major league level.