New England Patriots defensive lineman Armond Armstead retired last July at just 23 years old. In a statement released by the team, coach Bill Belichick said Armstead had dealt with an “unusual” amount of adversity.

We now have an idea of what Armstead was going through.

According to the Sacramento Bee, the former USC star is filing a lawsuit against his alma mater claiming that “fraud, concealment and negligence” prevented him from realizing his NFL dream.

Armstead suffered a heart attack while at USC in 2011 and believes it was caused by the school prescribing him painkillers. Yet documents filed in the lawsuit revealed that Armstead suffered a second heart attack in 2014, according to the Bee, and that the second health scare led the Sacramento native to retire.

Armstead went undrafted in 2012 but went on to play for the Canadian Football League’s Toronto Argonauts, helping the team win the 2012 Grey Cup while being named a CFL All-Star.

The Patriots signed Armstead in January 2013 but he never saw the field, undergoing surgery for an undisclosed infection in July 2013 and being placed on the reserve/non-football injury list in August.