Detroit Lions head coach Dan Campbell references Metallica in interview with NFL Network Insider Tom Pelissero at Lions camp.

Detroit Lions training camp has now progressed to the point where fan will be in the stands. The season ticket holders and VIPs are waiting to catch Saturday's practice, the first one open to anyone outside the immediate Lions den of media or family members.

Not many people watch the UFL in the spring, but Lions coach Dan Campbell says it's a place to see some talented professional football players — and he'd like to see it become an official NFL farm system.

Two Detroit Lions backups, defensive tackle Roy Lopez and running back Sione Vaki, are expected to be out for a few days, coach Dan Campbell said.

▶ For the second straight practice, Lions coach Dan Campbell had to stop the session to address physicality from the defense. It began even earlier on Thursday than it did Tuesday, with the primary beef of the day involving a pair of stars: All-Pro wide receiver Amon-Ra St. Brown and Pro Bowl safety Brian Branch.