no.. OOTP does not take over the names or origins.. but it does create new players with new default origins. Run the program again to modify the new players.. it will not change the players that were already in the league the previous season..
you can actually run the program anytime after the rookies are created.
When did you download the program? I updated a new version that corrected the problem with origin lengths that was causing a "input past end of file" errors. Also, feel free to send me your csv file after it is freshly exported from OOTP.
ptbl@pt-sports.com
HINT; never open the csv file in Excel or another spreadsheet program... if you need to , open it in notepad or something..