If you sign Jackson to a long-term contract, you have to take both guys and accept that the movie will always have an uncertain outcome, depending on the whims of a player who can't be controlled by either team.
Maybe that's a good bargain, but it hasn't been enough to convince the Eagles that the receiver is worth whatever price Jackson and agent Drew Rosenhaus have put on his signature.
For his latest trick, Jackson threw away a 50-yard gain against the Giants in the second quarter when he was so happy with himself that he flipped the ball nearly into the face of New York defensive coordinator Perry Fewell; did a few stupid, look-at-me gestures toward the opposing bench; and earned a taunting infraction.
That combined with a New York penalty to offset the entire play, and the Eagles were back at the 2-yard line, where they had started, and the drive soon stalled. On a night when overmatched backup quarterback Vince Young threw almost as many completions to blue shirts as to white shirts, it really wasn't a good idea to give one away for unnecessary preening.
"I had a little talk with him after that, make sure we were on the same page," Andy Reid said.
But that's DeSean. If you take the good, you take the bad.
As soon as you've had it with his antics and his little, hurt, uncomprehending face after he pulls another dopey move and gets punished for it, then he rips off a 51-yard punt return and reminds you why it might be a good idea to keep him around.
With Michael Vick and Jeremy Maclin out last night, the Eagles were a quart low on offensive playmakers. They needed Jackson to be a leader and help settle things down for Young, who definitely needed some help in that regard.
Young would end up throwing three interceptions and nearly threw another couple. For every pass that wasn't too bad - and he unleashed a few good, long efforts - there was another that was underthrown or overthrown and just badly thrown.
Every NFL team suffers without its starting quarterback, and Young had a right to be rusty, so he has to get some excuse room for Sunday night's effort, particularly when he slogged the Eagles down the field for a winning drive late in the fourth quarter.
The resulting 17-10 win was great for the Eagles and did nothing less than prevent the realistic end of their season, but it was an outcome for which the defense, not the offense, can take claim. The Giants didn't have good field position all night, and the Eagles defense saw to it that it remained that way. They did their usual thing of losing a fourth-quarter lead, but only briefly, and when Eli Manning tried to match Young's late drive with one of his own, he couldn't pull it off. Jason Babin hit Manning from behind to force a fumble and end the last chance for the Giants.
It was a butt-ugly game most of the night, but the Eagles aren't in a position to throw back wins based on style points. They also aren't in a position to have 50-yard receptions nullified because it's more important to be cool than be smart.
Jackson's body of work keeps growing. Previously in his career, he casually dropped the ball before entering the end zone, and also pulled off the difficult feat of being called for unsportsmanlike conduct while scoring a touchdown. Sunday night's rude flip was just more of the same.
Every time, he says that nothing like this will ever happen again. And every time it does.
To this point, Jackson's accomplishments are still on the positive side of the ledger, but all it will take is one of these goofs to cost a big game, perhaps cost a season, and that will be the play that he might be remembered for.
He's worth a lot of money, for sure, and, somewhere, he's going to be getting a lot of money. The Eagles know all of that, but they are taking their time with the contract, because they also know very well that the movie can have two endings.
Contact columnist Bob Ford
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Read his blog, "Post Patterns," at www.philly.com/postpatterns. Read his past columns