He was 26. The cause of death was not released.
"The Penn State football family would like to offer sincere condolences to the family and friends of letterman Adam Gress," Penn State said in a statement. "His commitment to this university and this program will never be forgotten."
Several of his former teammates expressed their condolences in the wake of the news:
"This is just awful news," former PSU teammate and fellow lineman Eric Shrive told Mark Brennan of 247Sports.com. "He was such great guy and so dedicated to the program. He was friends with everybody, and he worked so hard."
Gress spent five years with the Nittany Lions, starting for the team in 2013. He signed as an undrafted free agent with the New York Giants in 2014 but didn't make the team.