I propose that prior to every season commish team delegates 2 offensive and 2 defensive franchise players on every team that are untradeable. Star players, or star prospects, franchise cornerstone type players etc.

For example:

Houston Texans
1. JJ Watt,  Star player
2. J Clowney , Star Prospect, top 5 pick

1. Deandre Hopkins , Star Player
2. Lamar Miller, Star player

You know what, I like this..