The NFL scouting combine on Monday night sent a memo to all prospective NFL players attending next month's annual pre-draft event in Indianapolis, revising its policies and procedures regarding COVID-19 protocols.

The memo, obtained by ESPN's Adam Schefter, focuses on mask-wearing for both the players and medical personnel, as well as defining the event's secure areas, keys points of contention among players' agents.

"As has been the case throughout the pandemic, we continue to evolve our combine policies and procedures in consultation with medical experts," the memo said. "While masks continue to be required for air travel and during medical exams at the combine (players and medical personnel), wearing a mask at other times while on site is recommended, but not required.

"We encourage all players to remain within the secure combine areas at all times for your safety. However, if you would like to leave the secure areas during free time in your schedule, you are now permitted to do so at your own risk."

The memo landed hours after the potential of player boycotts made news Monday morning. Sources told ESPN's Dan Graziano that a group of player agents was threatening to organize a boycott of certain key elements of the combine if its concerns about a COVID-19 "bubble" continued to be ignored.

But not all agents were in that group.

"I understand their grievances, and they want to take their trainers with them to the combine, and they might want access to their agent. They might have family members. And they may have an entire support group both for their physical and emotional health -- and the NFL regulations seem unduly restrictive," agent Leigh Steinberg said Monday. "Having said that, we will send our players because this is the Super Bowl of scouting events. And you have players who have worked their whole lives to prepare for the NFL draft."

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. Monday night's memo featured amendments to further accommodate the players -- and their training teams -- at the event.

"If you prefer to remain in the secure areas and have your approved medical support personnel (physical therapist, massage therapist, or approved athletic trainer) enter the secure area to provide medical treatments, please follow the previously communicated procedure and complete the form in Teamworks (if you have not already)," the memo added.

This appears to be a direct result of pushback from the group of agents representing more than 150 of the 324 invited prospects. They said they would hold their players out of combine drills and interviews if the league did not relent on the original plans. Those players would, if the boycott were to be implemented, participate only in the medical evaluations at the combine. They would do their combine drills at their individual pro days instead of in Indianapolis.

Well into Sunday night, agents and the NFL were discussing the concerns in an attempt to avoid the announcement of the boycott, which the agents involved were tentatively planning for Monday, sources close to the situation told Graziano.

On Sunday, the NFLPA issued a memo to player agents in support of the idea of players skipping the combine, an event it described as "antiquated" and whose existence the union has long opposed.

Agents of incoming prospects furnish those players, at their own expense, with trainers, nutritionists and other specialists as part of their preparation for the grueling weeklong event at which they are measured, weighed, interviewed and tested on various skills. The agents have objected to recent changes that have moved some drills to prime time for TV purposes and compressed the amount of time the players have to get everything done while in Indy.

In particular, the agents opposed the idea of the bubble that would prevent players from interacting with some of the key people charged with making sure they're at their best for combine week. One source close to the situation said the nutrition aspect was among the most upsetting, since many of the prospects are trying to reach certain weights in time for the combine, and that effort could be upset by the last-minute decision by the league to be the sole provider of food for prospects at the event.

Discussions continued throughout Monday in an effort to reach a compromise, ultimately leading to the combine's decision and eventual release of the statement.

Last year's combine was scuttled because of the coronavirus, as were in-person visits, leading teams to rely on athletes' pro days in making their draft evaluations. This year's combine is scheduled to run March 1-7.

The Associated Press contributed to this report.