The Lions have agreed to standard four-year contracts with their four sixth- and seventh-round picks.
Virginia Tech receiver Corey Fuller, the highest Lions draft choice to sign, received a $123,000 signing bonus.
According to the Baltimore Sun, fellow sixth-rouder Theo Riddick, an all-purpose back from Notre Dame, received a $91,000 bonus, while seventh-rounders Michael Williams ($65,148) and Brandon Hepburn ($45,896) also finalized their deals.
The Lions were allotted a draft pool of about $7.5 million to sign their nine picks.
First-rounder Ziggy Ansah, second-rounder Darius Slay, third-rounder Larry Warford, fourth-rounder Devin Taylor and fifth-rounder Sam Martin remain unsigned.