I really like this idea.
Managers that wants to rebuild their roster can sell and buy not all in once - users need to know how to rebuild their team step by step.
The only issue I do see is if a day will come and a player will be worth 10M or more. but I really don't think that's something that should happen in the near future. This feature should be considering market prices.
"Did you miss me??? - "With every bullet so far..." Al Bundy