The Detroit Lions had another special guest at Friday's practice, the team's second day in a row with notable visitors on the scene. University of Michigan head football coach Brady Hoke and his staff were on the scene, but this was no ordinary social call for Hoke and his crew. They were there to learn something from their NFL counterparts.

Hoke, a former defensive line coach from his first stint with the Wolverines, furiously scribbled notes while watching the Lions defensive line go through drills. He later noted that the trip to NFL camp is an educational experience, especially for position coaches.

While at camp, Hoke and center Dan Gerberry hugged and spent a moment or two reminiscing about their time together at Ball State.

The Wolverines start fall practice next week on Aug. 6.

Read more on the Lions at Pride of Detroit and SB Nation Detroit. Head over to our dedicated NFL hub page for news and analysis around the league.