Absolut is correct.
The Cardinals outfield is very deep and is very talented. However, this is the first year for any of those starters being full-time players. As a matter of fact, the only person in the outfield who may start every game is Ankiel. He obviously has the most fantasy value. As for Duncan and Ludwick, they can switch off a lot and neither of them will more than likely start a whole week straight.
The Cardinals don't have a leadoff guy who is any good if they start Ludwick, Ankiel, and Duncan. To combat this, the start Skip Schumaker start often because he is a leadoff type guy. They also have Brian Barton as an outfielder who has a little over 1/3 of the games because he can leadoff and he brings some speed to the Cardinals lineup. Because Ludwick and Duncan can't leadoff and Duncan can't hit lefties......you will see a lot of time split in the corner outfield positions between Duncan/Ludwick/Schumaker/Barton.
So, yes I do believe they are for real, but for the aforementioned reasons, Ludwick and Duncan lack fantasy value.