It's bad when the guy you're expecting to give your offense a spark is Matt Cassel.

There are a lot of words that can be used in the same sentence as Cassel. Spark isn't usually one of them. Yet that's what the Dallas Cowboys are hoping to get from a guy who has bounced from Kansas City to Minnesota to Buffalo and now to Arlington, all the while looking like anything but a spark plug.

It's not like Cassel can make plays with his legs when things break down. Teams often like to have that kind of ability in their backup quarterback because, let's face it, he's a backup for a reason. That reason is usually that he can't do as much as the starter with his arm.

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But when you look at Cassel compared to Brandon Weeden, who has been told he's no longer the starter in Tony Romo's absence, is there that much of a difference?

What will Cassel be able to do with a corps of wide receivers that's proven to be a bunch of role players who can't create without Dez Bryant drawing attention elsewhere? Will Cassel be able to get Terrance Williams open? Will he be able to make Devin Street run faster so he can be a size/speed guy who can offset the loss of Bryant? Or will he look up as Weeden did on third-and-3 from his own 20-yard line in the first quarter on Sunday and see all four of his targets blanketed by Patriots defender? Nobody was open. Not even close. And Weeden was sacked.

Will Cassel improve a running game and an offensive line that were supposed to be the strength of this team?

OK, so maybe those things could be more of a strength for Cassel. Perhaps he'll make the smarter pre-snap reads and set the protections to make his blockers more effective, though not nearly as well as Romo does it. Remember that Cassel's next live snaps, which will come against the New York Giants in Week 7, will be his first as a Cowboy. The team acquired him just three weeks ago.

The truth is Weeden wasn't playing that badly, not when you consider what was happening around him.

Weeden connected on all seven of his pass attempts in relief of Romo in Philadelphia, then went 22-for-26 and 16-for-26 in his next two games. After leading a tying touchdown drive in New Orleans (he was 5-for-8 for all 91 of the Cowboys' yards on that drive), he never got a shot in overtime against the Saints because the defense gave up an 80-yard touchdown to C.J. Spiller.

The point is it's difficult to see right now how Cassel, having worked with his new team in his new playbook for only a few weeks, will be a better option than Weeden. And let's not forget the Bills, who will likely sit Tyrod Taylor this week and maybe next because of knee and ankle injuries, dealt Cassel to Dallas while Taylor was battling through an ankle injury FOX's Jay Glazer first reported was worse than people realized. So they had to know at the time there was a chance they'd need their backup quarterback at some point, and they were apparently comfortable knowing it would be EJ Manuel instead of Cassel.

Jason Garrett is a former quarterback and a damn good coach, so he surely sees something warranting a change here. But if he's expecting a spark and some fireworks to follow, he's mistaken.