When the draft ends, NFL teams commence a land rush for undrafted rookies. This year, the Patriots have not participated in what otherwise is a knee-jerk ritual.
Mike Reiss of ESPN.com explains the reasons for the decision to wait.
First, uncertainty regarding the pandemic has prompted the Patriots to remain at 82 players on the roster. Last year, the NFL and NFLPA gave teams the option to proceed with a split squad (if taking 90 to camp) or a single roster (if taking only 80). The Patriots opted for 80; they had to cut some undrafted free agents to get to that number. Some of them, as Reiss notes, had guaranteed money in their contract.
Second, the pool of undrafted players is more shallow this year, because fewer total players signed with agents.
Per Reiss, coach Bill Belichick has said that the team will invite potential undrafted free agents on a tryout basis later in the offseason. For now, the delay primarily seems to trace to the question of whether teams will have to make the same 80 vs. 90 decision when camp opens.