The attributes of the player are located in the file
Load it into a hexeditor and search for the name of
the player you want to edit.
Behind the name there are a lot of 00, about 11 to 14
pairs (Don't touch them).
But the next 13 bytes you could change, maximum number is 64:
The Bytes: AA BB CC DD EE FF GG HH II JJ KK LL MM
AA and BB: position of the player, CC: fastness,
DD: stamina, EE: power, FF: power of shoting,
GG: precision of shoting, HH: ability to control the ball,
II: passing, JJ: tackling, KK: intelligence, ll: fitness,