According to Birkett, Vanden Bosch lowered his $5 million base salary to the league minimum ($925,000) and took the remaining $4.075 million as a signing bonus.
Since Vanden Bosch was signed through the 2013 season, in order to maximize the short-term cap savings of the restructure, the Lions added two voidable seasons onto the contract, with base salaries of $8 million in both 2014 and 2015, to allow the bonus to be prorated over four seasons.
The simple restructure lowers Vanden Bosch's cap number from $7,667,500 to $4,611,250, a cap savings of just over $3.05 million for the 2012 season.
As Birkett noted, the Lions were around $700,000 over the cap earlier this week, so the additional room will allow them to carry a practice squad and make some roster moves over the next few months.
While the Lions do gain some immediate salary-cap relief, the restructure also increases Vanden Bosch's 2013 cap number to over $10.6 million.
After this season, the Lions may need to make a hard decision on what will be a 34-year-old defensive end, who according to a source with knowledge of his contract, is scheduled to receive a $2 million roster bonus on the seventh day of the 2013 league year.
Follow Brian McIntyre on Twitter @brian_mcintyre.