Detroit's first workout of the regular season was a light practice that saw most of the team's injured players return to action. Defensive end Kyle Vanden Bosch (knee), running back Kevin Smith (ankle) and cornerback Bill Bentley (shoulder) all participated in drills open to media after being held out of the Lions' preseason finale.

Cornerback Chris Houston (ankle) and safety Louis Delmas (knee) were the only players who weren't present during the open portion of practice, but they were able to work with trainers in hopes of being ready for Wednesday's practice.

Houston's absence created an opportunity for newly-acquired corner Drayton Florence to take some first-team reps at both the right and nickel slots. He rotated with Bentley and Jacob Lacey, along with fellow newcomer Kevin Barnes.

Coach Jim Schwartz did not address the rehab progress of Detroit's injured defensive backs.

“I’ll be in regular season mode (where he does not discuss) injuries from now on,” he said. “We’ll have an injury report (Wednesday) and go from there. We’ll get (Delmas and Houston) back as soon as we can.”

Report: Lions over salary cap: For the second time during the 2012 calendar year, the Lions will need to restructure contracts to comply with the NFL's salary ceiling. ESPN reported that Detroit is roughly $700,000 over the league's $120.6 million salary cap.

The discrepancy is likely due to the acquisitions of Barnes and Florence. The team has until Wednesday to either release players or restructure players' contracts to create cap space.
Players' contracts are restructured by converting a portion of their yearly salary that counts against the salary cap into a signing bonus that can be paid immediately, but spread out over the life of the contract for accounting purposes.

Detroit restructured the contracts of receiver Nate Burleson, defensive tackle Ndamukong Suh and quarterback Matthew Stafford to comply with the cap deadline before the start of the 2012-13 league year.

Silva waived: Safety Ricardo Silva, whose play on the Lions' practice squad last season earned him an elevation to the active roster, was waived Monday when the Lions finalized the signing of Florence. The move is slightly puzzling, since Silva's departure leaves Detroit with just three healthy safeties until Louis Delmas returns to action.

Schwartz told reporters before Friday's roster deadline that he wasn't afraid to “go light at a position” to keep talented players in another position group, and the decision to waive Silva supports that assertion.

If Delmas isn't healthy enough to return to action in Week 1, Barnes could see time at safety on an emergency basis.

Follow Lions reporter John Kreger on Twitter at @CBSSportsNFLDET and @JohnKreger.