Then it will be possible to buy 160% of the player at the price of 99%. You can cancel the bet and continue training the player.

On the contrary, I would suggest making it possible to add a player to the negotiation list so that he does NOT receive experience from training. Do the same as now "put up for auction". It's a shame when your 99% trained player gets 4% skill from your friends and is removed from the negotiation list until next season.