In all of the trade rumour articles, AJ is consistently mentioned as "the top starting pitcher" available in trades. If that was the case, you'd have to believe the Phils would have been willing to offer Cardenas in a package for Burnett.
Obviously the big difference between AJ and Blanton comes down to two things - club control and money. Blanton costs 3.7 million this year, of which the Phils will pay a prorated 1.5-1.8 million. They also control him for another two years, which is a huge plus. AJ would cost them a prorated 6 or so million dollars, while having the ability to opt out at the end of the year.
But for a team that currently tied for first place, you'd think acquiring the superior talent would be more valuable to the Phils. If they were to sign AJ to a long-term deal, in order to avoid the opt out, they'd have Pat Burrell's 12 million coming off the books in 2009. Not that it's a good move to let Burrell go, but I get the feeling they just don't appreciate his value and won't pay him what he's worth. While Will & Johnny have recently suggested Manny as a DH for next year, I'd like to suggest Pat Burrell. He's usually got an OBP near 400 and a slugging above 500 - he's the bat this team needs.
But back to AJ and the Phils - if they wanted to win, it'd make more sense to go with the guy who has a 108 career ERA+, and is capable of putting up a 115-119 ERA+ in a home park that is known to be good to hitters. They wouldn't have to worry too much about home and away splits like they do with Blanton, who's been a career 4.78 ERA pitcher away from the pitchers park in Oakland (compared to the 3.79 in Oakland for his career).
Blanton has a 100 career ERA+ - he's an average starting pitcher. He's not a strong GB pitcher, so he'd be bound to give up more HR's in Philly. He'll be an upgrade over Adam Eaton, which I guess makes them a better team, but upgrading from horrible to merely shitty is nothing to be happy about. Blanton's still going to cost them games because of his inability to strike out hitters, and his reliance on defense (for which the Phils aren't that good).
What does this mean for the Jays? Despite all of AJ's talents, it's very likely he won't be traded before the deadline. JP has never made that big trade at the deadline, and he's had several candidates which could have been traded (Wells in 2006 before he signed the contract extension would have been creative). If the Phils were willing to give up a solid 2B prospect for Blanton, and not for AJ, it paints a pretty clear picture on how high clubs are on Burnett.
If the Jays really want to trade Burnett, I think it might help if they give a 72 hour window to give the team a chance to amend the opt out by adding extra $$ for AJ. No, they shouldn't have to do it, but that opt out is going to be the biggest reason why AJ has a better chance of opting out when the seasons over than he does of being traded. You do that (the 72 hour window), and you get the right to ask for superior prospects. And if you can get the extra prospects, than it's worth it to let the team talk to him before hand.