Here's the problem with trade speculation: a deal that might make lots of sense sitting here in Center City might be a non-starter to a trade partner for reasons we just can't see from Philly.

Every coach and GM has philosophies, quirks and plans that might make certain moves unthinkable and others quite predictable. (For example, how surprised would anyone be if Andy Reid traded down in the next draft to pick a fast, somewhat smallish defensive end? But you'd be stunned if he decided to invest big in a power running back who couldn't really catch the ball.)

But while Eagles beat writers and fans know Reid's habits well, we have less engagement with the rest of the league to know their bedrock philosophies. Which is a long way of saying that while we know what the Eagles think of Kevin Kolb, and what trade scenarios might make sense for them (or at least make worthy blog/Twitter/chat fodder), we know less about how potential trade partners view the situation.

Which is what made a recent blog post from Kent Somers of The Arizona Republic valuable reading. He added a fair bit of kindling to the Kolb-to-the-Cardinals fire – being that his views come from someone who follows the Cards closely – but also cast doubt on thoughts that Arizona would give up the kind of haul Eagles fans and executives might dream about.

"There is no question the Cardinals are interested, and I get the feeling Kolb is their first choice to be their starter in 2011," Somers writes. "The Cardinals liked Kolb when he was coming out of the University of Houston, and he has the type of personality (gym rat) that Cardinals coach Ken Whisenhunt likes in a quarterback."

So far, so good. But then there's this:

"The Cardinals are leery, however, of what the Eagles might want for Kolb. If the Eagles want to use the (Matt) Schaub trade as a template, I think the Cardinals would be interested."

The Schaub trade was two second rounders for the then-Falcons backup, plus a small change in first round position (Houston moved down to 10th, Atlanta up to 8th). Nice, but not the blockbuster forecast by rumors of first round offers. (These rumors, it should be noted, never included details about how high the pick might be, or if the Eagles would have to give up anything in addition to Kolb to get the first rounder).

Somers' perspective is a nice reminder that for all of the Eagles' talk about how good Kolb is, and how much he should be worth in a down QB market, he's still a guy with seven career starts; a guy with the potential to be good and young enough to still have a long career, but who has never started more than three consecutive games. Which is to say he's a guy whose value can be strongly debated, and surely will be by any trade partner.

Somers mentions that maybe the Cardinals could give up a first rounder in 2012, given the possibility that Kolb could help them win a weak division and drive down the value of the pick. He makes no mention of the Cardinals looking to deal players – though obviously that might change if the Eagles were to make a specific demand and the Cardinals really do love Kolb.

But the Cardinals' willingness to give up a player who could help the Eagles right away (corner Dominique Rodgers-Cromartie is the new hot idea among Eagles fans) will depend not just on any perceived fairness from the Philly perspective or the "on paper" implications. Much will hinge on Ken Whisenhunt's vision for his team. If for whatever reason Rodgers-Cromartie is a key piece of some grand plan, forget it. And we just don't know that yet. It's maybe an obvious point, but one that seems too often to get lost in the "what-ifs" of the trading game.

(And for that small number of Eagles fans clinging to the Patrick Peterson fantasy – let me reiterate that it will be better for everyone if you just let that go).

This week's Sports Illustrated adds another voice to the Kolb-to-Arizona chorus. SI's Jim Trotter lists the Cardinals and Seahawks as the top players for Kolb, reporting that the Seahawks pursued him last year. But, he says, Seattle believes in building through the draft (another nice glimpse into another team's philosophy that factors into any deal) and so Trotter think they're unlikely to give up high picks for Kolb. "Arizona is desperate," Trotter writes, because they need a solid QB to appease Larry Fitzgerald.