Like your drive for suggestions, but can you tell me what are you trying to curb? You wrote an idea, however there is no explanation what is suppose to tackle down.
What I see is almost complete control over the market which most likely will have a footprint on vanishing liquidity - max return, or rather minimum loss cause you cannot make profit, on non-trained players (that is like 90% of them) will push me back from listing players.
As I agree that it is worth to think about some limitations around players rotation in one club (trading club rather than basketball club), but not the way as you presented.
I am totally against any profit limits imposed on clubs as it has nothing to do with free market. Market should naturally adjust to prevailing conditions and it does so. The inflation is a result of maturity of clubs and shrinking user base. If you see that market is overpriced then just start training and sell young player with a profit. Soon, you will have many followers and market will be again flooded with well-trained players (and ultimately lead to price decrease).