By Matt Audilet As he heads into the final season of his rookie contract, Lamar Jackson has yet to sign a longterm extension deal with the Baltimore Ravens. When talking to media yesterday, Ravens GM Eric DeCosta indicated that the Baltimore organization hopes to get a deal done with Jackson whenever “he wants to work on it.” The wording of this message seemed to imply that the former league MVP could be set to test the contract waters. With Jackson seemingly in no rush to get a deal done, NFL Network insider Ian Rapoport suggested that the superstar QB could play his existing contract all the…