In recent memory, only college seniors had been permitted to play in All-Star showcase games, including the Senior Bowl and Shrine Bowl. This rule kept some of the top underclassmen who declared for the NFL draft from participating in such events, limiting their exposure to just the NFL Combine and their respective Pro Days.
However, it appears that restriction is coming to an end. According to ESPN NFL insider Adam Schefter, all college juniors who declare for the draft will be eligible to play in the All-Star showcases.
Per Schefter, the league sent a memo to all 32 teams today announcing the change.