The OOTP DAT files are game data files and they can be opened with a hex editor (strongly not advised though). In order to program a utility to edit player info (unretire the player) you would need the data structure, informing you what information was stored where in the data file in question. If you are are programmer & want to create a utility you could write to Markus and explain your situation. If you are not a programmer then having the DAT file structure won't be helpful anyway

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