Fifa have permitted an expanded squad size for the tournament, with countries now permitted to include up to 26 players in their selection, with a minimum of 23.
Each nation’s final squad must be submitted by 13 November 2022, one week before the World Cup begins on 20 November.
The replacement of injured or Covid-19 positive players will be permitted until 24 hours before the start of a team’s first match in Qatar.
However a provisional squad of up to 55 players, referred to as a “release list” by Fifa, will be submitted sooner.
Southgate is likely to name this expanded group later in October.
The England squad for their final fixtures before the tournament against Germany and Italy was formed of 28 players.
Everton’s Jordan Pickford was among those absent from that group, though, and Southgate’s likely first-choice goalkeeper will almost certainly return to the selection for the tournament.
Kalvin Phillips, meanwhile, was forced to pull out of the squad for the two Nations League fixtures after undergoing shoulder surgery and faces a race to prove his fitness for the tournament.
Southgate’s toughest decision may come at right-back, with four proven options perhaps competing for only three places.