A group of player agents is threatening to organize a boycott of key elements of the NFL scouting combine if its concerns about a COVID-19 "bubble" for prospects are not addressed, according to sources.

The NFL sent a memo last week to draft prospects and their agents outlining rules for the combine, including a "bubble" that would keep prospects from interacting with their personal trainers, doctors, nutritionists and agents while in Indianapolis.

A group of agents representing more than 150 of the 324 invited prospects has pushed back, saying it will hold its players out of combine drills and interviews if the league does not relent on those plans.