Will the Rams add a running back?

With the St. Louis Rams moving on from lead back Steven Jackson this offseason, that's left a bit of a vacuum at their starting RB slot. Daryl Richardson had his moments during his rookie campaign of 2012, but it's not believed that he necessarily projects to being the same caliber of lead back as Jackson. Meanwhile, fellow rising second-year pro Isaiah Pead has a higher draft pedigree, but the buzz on him is that he projects to being a change-of-pace RB. So will the club make any additions from free agency, given the talent that remains available?