The Dolphins and the Vikings found out the hard way. If Mike Wallace is a one trick pony, the Ravens should think smarter, and not for him into roles he has previously failed in.
His contract however, seems to indicate that the Ravens think of him as a legitimate number two receiver. While that projection could come to fruition, it is exactly that. A projection.
When Wallace was signed, most pointed to his role being similar to that of Jacoby Jones' in the 2012 receiving corp. A deep threat that would contribute in spot duty.