ok 1st step get latest roster.ros you can your going to need to edit this baby ,any player that is close to 40 years or retiring your going to have to set there birthday up 5 years making them 5 years younger.
Next step goto there contract year after you move them to the right team. Add years 1st year is 2012 x 4 is 2016 save your roster.ros ps if any player has changed postion fix it in there ps hanley ramirez.
now in game simulation turn off injuries and make sure after any year that you sim you make sure your teams lineup and pitching are correct inclueded that your manager hasnt left update and sim to the next till you get to 2016 best i could do .