"I do believe fitness is going to be an issue," Wagner said.

Thompson, 28, of Lombard pleaded not guilty to a five-count indictment charging him with first-degree murder.

He is accused of killing his neighbor, 66-year-old James Malone, by throwing him off a balcony in the building where they lived on March 30. Thompson surrendered to authorities that evening after a nearly seven-hour standoff with police.

Thompson was a standout athlete at a suburban Chicago high school and played defensive end at Michigan State.

The New Orleans Saints signed Thompson in 2000. But he was cut before the start of the season after getting into a dispute with a teammate during a workout.

Thompson’s mother, Maggie Ross, has said doctors diagnosed her son with bipolar disorder and that he had stopped taking medication because the drugs made him feel listless and dizzy.