Leonard Marshall glanced at the video screen as the highlight that helped define his NFL career played.

Once the clip of his bone-crushing hit on San Francisco 49ers quarterback Joe Montana in the 1991 NFC Championship ended, Marshall wryly noted, “That play would cost me $250,000 if I was still playing today.”

Marshall is still an imposing presence at age 53. The former LSU and New York Giants star came to the Louisiana High School Coaches Association’s Coaches Clinic armed with a message that went beyond an opening one-liner.

“It’s imperative for folks to understand that there’s a responsibility to educate and eradicate concussions and to help people understand what traumatic brain injury really is,” Marshall said. “My message is not to stop playing football. It’s to be smart about teaching it, coaching it and playing it. You have to play it with safety in mind.”

The Franklin native teamed with Dartmouth coach Buddy Teevens and Terry O’Neil, a broadcaster who worked with the New Orleans Saints during the Mike Ditka era, to present the “Practice Like Pros” program designed to reduce concussions by reducing contact drills in practice.

Marshall was the “closer” for the three-man presentation Wednesday at the Crowne Plaza.

Afterward, he visited with coaches, including former LSU strength coach and current Dunham assistant coach Tim Jorgensen, trading jokes and stories.

“I love the fact that I’m from Louisiana,” Marshall said. “That means more to me than anything.

“I’m proud of the fact that I played biddy basketball for Ray Landry and I can count (the late) Dick McCloskey (legendary Hanson Memorial coach) as a mentor.

“One of my father’s proudest moments was when I was inducted into the (Louisiana Sports) Hall of Fame. I love the food. I love everything about this state. The plan is to retire one day.”

Marshall hints that his “retirement date” may not be too far away.

For now, he splits time between homes in Boca Raton, Florida, where his youngest daughter is in college, and New Jersey.

Marshall is planning to return to Baton Rouge for two LSU games this fall.

In the years since 1994, when his NFL career ended, business has been very good for Marshall. He talks about a recent deal he brokered and plans to sell a restaurant chain he holds an interest in.

He has a master’s degree from Seton Hall and spent the 2010 season as head football coach at Hudson Catholic in Jersey City. So it’s fair to say the man nicknamed “Big Cheese” at LSU is one.

Marshall’s appearance at the LHSCA clinic was anything but corporate lip service. He told the crowd that he displays the symptoms of chronic traumatic encephalopathy or CTE. Afterward, he said he’s in the early stages of Parkinson’s disease.CTE is a progressive degenerative disease that can only be diagnosed postmortem in individuals with a history of multiple concussions.

Marshall carries a picture of his brain scan in his cell phone and joined former NFL players in their concussion lawsuit in 2011 after his friend, former Bears safety Dave Duerson, committed suicide.

Marshall has his own initiative, brainunitytrust.com, but was sold on “Practice Like Pros” and got involved six months ago. It now has roots in 39 states.

“Do I wish I knew all the things we know now about concussions when I played? Sure,” Marshall said. “But I still think football is a great game. It just has to be approached the right way.”