Any deal would be exceedingly difficult, and the value coming back would be a lot less than people might think.
Both of which are good reasons why the Red Sox wouldn't do such a deal, and probably wouldn't even broach it. DiceK would have to be a problem for such a deal to get anywhere up the deal-making priority list. He's not a problem -- he's just not effective, yet.
His inefficiency while working--which may actually be a key to the success he does have--has the potential to stress the bullpen anytime any of the other starters are scuffling, and limits his value to the team.
I have no idea what's going on with him this year. His K/9 and BB/9 look like DiceK, but the HR, BABIP and AVG are all way up, and it doesn't look like bad luck. I tend to think he's injured, but a part of me wonders if the rest of the league has just caught onto him and will wait for the mistake. I'll let the f/x junkies solve that one.
I agree that nibbling (= inefficiency) is a problem for the average staff, but given this year's bullpen arsenal, it's less of a problem for the Red Sox.
I don't think the pitchfx data can tell us much about the approach of the rest of the league. It can't really do much more than show that DiceK's velocity isn't back to normal and that his slurve, normally his best pitch, is less effective than last year. I do have some subjective impressions, though: I think his command of all his pitches has not yet come back since his spectacular performance against Cuba, and without better command, he can't nibble effectively because he is wild(er) in the strike zone than he was last year.
His stamina isn't back to normal after his DL stint, and when he tires, it shows first of all in loss of command -- leaving all his pitches up in the zone was the proximate cause of his downfall against the Phillies. His velocity is getting a little bit better, but he needs to sit at 93, not 91, if he wants to get away with the occasional mistake. His changeup gets hit too because it doesn't always work. He doesn't throw the changeup very often because he doesn't know whether it will dive or hang. He has taken to throwing the cutter more often when he needs a strike because it's the one pitch he has been placing pretty well.
He's still pitching like he's just out of spring training. I expect him to improve to a respectable third starter by mid-season, but like Papi's, his total season results will probably look mediocre.