Even though he only called 5 or 10 trick plays when he was the offensive coordinator for the Pittsburgh Steelers, everyone seems to associate Ken Whisenhunt with trick plays. And that's about all they associate him with. There is, however, a lot more to the new Cardinals head coach and there's a lot more to his schemes. First and foremost, all the plays he likes to run (the other 99.99% of them) that aren't trick plays.
One other hallmark of the Whisenhunt system during his days with the Steelers was the fact that he called copious amounts of running plays, especially during the first two years of Ben Roethlisberger's career, which was ostensibly to shelter the young quarterback from himself. It had a lot to do, though, with the fact that Whisenhunt didn't have a whole lot of talent on the roster beyond Hines Ward. Plaxico Burress was hurt for a few games in 2004, then gone in 2005 and 2006. Antwaan Randle El was a return specialist and third receiver (in an offense that didn't throw much) in 2004, caught 35 passes in 2005, and was gone in 2006.
While he has, historically, called significantly more running plays than passing plays, he's also never had the talent on board that the Cardinals have in Aquan Boldin, Bryant Johnson, and... Larry Fitzgerald. He has made a point of saying that he will tailor his system to the talent he has on the roster. Since Arizona has Edgerrin James and pretty much no one else at running back and all kinds of talent at the wide receiver position, this means we're not likely to see a lot of "three yards and a cloud" of dust out of the Cardinals this season.
What does that mean for Fitzgerald? Well, even though Whisenhunt is going to throw the ball more than he did in Pittsburgh, he also has considerably more talent in the desert than he had with the Steelers. That means that after Johnson and Boldin get their share, there will not be as many balls left for Fitzgerald to catch. While Whisenhunt is at the controls, it is highly unlikely that we'll see a return to the days of 2005 when both Boldin and Fitzgerald had 1,400 yards receiving.
However, that doesn't mean that Fitzgerald will see a huge decline in yardage, simply a decline in recptions.
Whisenhunt's system is predicated off of establishing the run, mixing in a variety of pass plays to a variety of depths early on, then attacking vertically off of playaction. While it remains to be seen whether or not Arizona will actually get anything started on the ground, they have more than enough weapons at their disposal to mix in the pass and attack down the field.
Fitzgerald is a very accomplished route runner and can use his superior size and body control to get "open enough" and beat the defender to the ball at any depth. He has shown flashes of this on deep passes in his time with the Cardinals, but his old quarterback at Pitt used to throw the ball as high as he could and watch Larry fight for it (and come down with it most of the time - there's a reason the man was drafted third overall in 2004). His receptions may decline, but he will most assuredly improve upon his 13.5 average yards per catch from last season.
The pass patterns most commonly "mixed in" while Whisenhunt is establishing the run are the slant, the hitch, and the post (both skinny and deep). In his time in the NFL, the one area that Fitzgerald has improved upon the most is using his size to get between the defender and the ball in tight areas. This is a skill he will have to utilize repeatedly when running the skinny post and the slant, but he will also be able to draw upon his superb route running skills to run crisp posts and get open in the soft part of the zone before the opposing defense has a chance to maul Matt Leinart.
Overall, he will fit in well. Fitzgerald is a great receiver and great receivers are an asset to any offensive system. But, Fitzgerald seems to fit this particular system especially well and should see a more productive season this year than any other receiver on the roster.