Marshall has started 32 consecutive games for Carolina and 46 overall since entering the NFL with the Panthers in 2006. He's relatively young (26) and has seven interceptions over the past two seasons.
Though the Cardinals presumably want their cornerbacks to support the run effectively in the scheme first-year coordinator Ray Horton is bringing from Pittsburgh, Marshall is known more as a cover corner than for his strength or power.
The market for cornerbacks, dominated by Nnamdi Asomugha's massive deal with Philadelphia, has quickly evolved to include players taking lower-profile deals. The St. Louis Rams added veteran Al Harris on Friday. The San Francisco 49ers and Seattle Seahawks could also use veteran help at the position, in my view. Quite a few 49ers fans I've heard from will second that notion.