More definitive word is likely coming by week's end (possibly as soon as tomorrow) but it looks as though Spring Camps in Florida and Arizona will officially open next Wednesday, February 17th for officially six weeks.
Each team is going to play 28 Spring Games (after a week or so of practicing and conditioning), with extremely little travel involved (E.g. the 30 clubs will be split up into six "pods" and only play amongst teams in their designated pod).
There won't be any split-squad games on the schedule (I.e. MLB will nix the often used one home and one road game double header schedule), this makes sense as travel is being minimized and the number of players in camp will be cut.
The facilities are likely going to be closed to the public, i.e. no attendance.
Each team will be limited to how many players they can have in their spring camps. Meaning, each club is likely only going to carry 40 man roster players, players on MiLB deals who have a legit chance of making an opening day squad and are destined to play in AAA if not (in any given year there are usually around 300 players on MiLB deals with past MLB service time), and top prospects.
The numbers aren't set in stone as of yet, but it will likely be around 80 players per team - somewhat similar to the 60-man player pool used in 2020 for the MLB alternate sites.
Mandatory testing will be in-place for all players and staff.
The AAA season is currently slated to open in conjunction with the MLB season in early April, meaning that most of the players who are in the initial camp who don't make the MLB opening day squad will be assigned directly to their AAA affiliate for early April games. This ensures there is a ready pipeline to MLB clubs to fill-in for injuries. No word on whether any of these 30 AAA clubs will be allowed in-game attendance out of the gate.
There will be a second spring camp set up immediately after the MLB camp precludes that will welcome in all of the 30 organization's other minor league players, this will be a slightly larger group (perhaps as many as 120). These players are destined to start the 2021 season in AA, A+, and A level ball. The season for those 3 levels will be delayed by at least a month.
A "third" camp would then take place in the AZ/FL/and Dominican parks for players assigned to those "rookie-level" rosters. These teams may be forced to run more as an instructional level rather than competitive in 2021.
Salary increases for all full-season minor leaguers will take effect this season, 2021 minimums for players on minor league contracts (e.g. non-40 man roster players), will rise from $290 weekly to $400 at rookie levels, from $290 to $500 at Class A, from $350 to $600 at Double-A, and from $502 to $700 at Triple-A.