Alright... so lets try this tool out:
http://nflblitzfans.com/index.php?topic=50.0Step 1 would be to covert the chd to a raw drive dump.
Then using the team editor tool:
Select Arcade for System and Blitz 2000 for game.
Click "Pull Roster from ROM"
Select the Blitz2k.raw file.
It should load all the teams with players.
Edit a player, click save roster to rom.
Select the same raw file.
Image the hard drive with this edited raw file.