Keeping the lowest salary possible is actual a good plan for now.
The game manual clearly states:
The salary floor does not apply to new teams for their first sixteen weeks
So for the first sixteen weeks of his team, he should keep his salary as low as possible. (if he is going with his hoard money strategy) and you would only have to have three players.
Personally if I was to follow this strategy I would want to buy 3 18 year olds with around allstar potential so that I could train all three of them throughout the year as well, increasing their value throughout the year and thus gain potential revenue if you did choose to sell them (even if you are using a minimal trainer... some training is better than no training.)
After the first 16 weeks are over, however, I would definitely recommend a different strategy.