and a punter to be named later

[spodog]

Always kind of wondered about this. In baseball, it is not uncommon to see two teams complete a trade that includes a player to be named later.

Don't ever recall this happening in the NFL.

Maybe because the salary cap doesn't allow teams to make these kind of trades where their financial commitment is open ended?

Maybe because of the lack of a minor league system?

If it's the former, does an uncapped 2010 year mean we might actually see trades like this in the upcoming year?

Thoughts?