My Master League team has 2 good left backs, and no good right backs. Is there a way I can train one of them to play on the right? (At the moment, they both suck in that position). Do I up their athletic ability training? I don't seem to be able to get them to retrain for that position, since they already have SB...
Off the top of my head (I've not played Pro Evo in a couple of years) I don't remember it being possible to change a player's side as it is their natural-footedness that the R/L represents.
The only way I reckon you'd be able to do that is if you can still edit players individually via the game's editor? You could use this to boost your player's Weak Foot Accuracy (set it to 8 or more) and Weak Foot Frequency. Even then, if you make changes, it may not be possible to add them in to your existing Master League since the game's already underway.