The club offered arbitration to both players in order to ensure that it will receive Draft pick compensation when and if they leave via free agency. If a player accepts arbitration, it is tantamount to signing a one-year deal with the offering club. Given that both Pujols and Jackson are likely to receive multiyear deals this winter, it would make little sense for them to accept.
Pujols is a Type A free agent under the final year of a system based on ratings established by the Elias Sports Bureau. That means that if he signs with another club, the Cardinals would receive the signing team's first- or second-round pick as well as a compensatory "sandwich" pick between the first and second rounds.
Jackson is a Type B free agent. If he signs elsewhere (which appears virtually certain), the Cardinals would receive a sandwich pick but not a pick from the signing team. The Cardinals will also be compensated if Octavio Dotel signs with another team, and it appears that Dotel will imminently sign with Detroit. Dotel's status was adjusted from Type A to Type B, and as a result, St. Louis did not need to offer him arbitration in order to be compensated.
Matthew Leach is a reporter for MLB.com. Read his blog, Obviously, You're Not a Golfer and follow him on Twitter at @MatthewHLeach. This story was not subject to the approval of Major League Baseball or its clubs.