Use Microsoft access to open old player file in your season save folder and copy the following files to the new player file.

CSFGATT-CSEJECT
CPFGATT-CPEJECT
INJURYID
INJURYDATE
RECOVERYDATE
INSEASON
WEEKLYMVP
MONTHLYMVP
WEEKGAMES
MONTHGAMES
RAWOFFVAL
OFFVALUE
DEFVALUE
PGSTART
PEJECT
I think this is how you do it, but let me know if i need more old player files to replace the new player file.