Compensatory picks in the NFL are a funny thing. I have no idea who awards them, except that the league hands them out.
The reasoning for them is even more odd. Compensatory picks are given to teams based on the contract value of players that left the team, minus the contract values of players the team signed. Like this....
The Los Angeles Chargers los, via free agency last offseason, Eric Weddle (to the Ravens), Ladarius Green (to the Steelers), and Patrick Robinson (to the Colts).