The following bench players, many of them who are "should be starters," are avaliable for relief pitchers.
Pedro Feliz (2.5 stars)
Ryan Freel (2 stars)
Craig Wilson (2 stars)
Mark Kotsay (2 stars)
Johnny Estrada (3 stars)
Ryan Klesko (2 stars)
Klesko has a big contract so it would only take a 2 star RP to get him. For the others, I value batters more than relief pitchers (I'd say RP are easier to sign in free agency than batters), so it would probably take someone a bit better (in terms of stars) to get him. Of course, stars aren't everything either. Offer me a RP with good ratings and I'd consider it as well.