With the Patriots designating FB Reggie Gilliam to return from IR, and WR Romeo Doubs and LG Alijah Vera-Tucker likely being locks to return as well, New England would have just one IR return designation remaining for the regular season.
I’d imagine they hold onto that final designation until at least Week 14 to maintain flexibility in case another player lands on IR.
If New England makes the playoffs, it would receive two additional return designations.