UEFA has advised that the 2020 summer transfer window should close no later than October 5.
Nottingham Forest do not know yet what division they will be in next term, as they resume their push for promotion on Saturday, but they are likely to want to make changes to their squad regardless.
Dates have not yet been set, however, for when they would be able to bring in players.
The transfer registration period in a number of European countries, including England, has not yet opened because of the delay in finishing the 2019/20 season due to the coronavirus pandemic.
European football's governing body has set October 6 as the deadline for the registration of players to compete in the Champions League and Europa League group phase, and has therefore recommended the transfer window closes the day before.
A statement by UEFA on Thursday read: "The deadline for player registration for the group stage of the 2020-21 UEFA club competitions has been set to October 6, 2020.
"As a result, the UEFA executive committee called on all member associations to adopt a harmonised end date to the upcoming summer transfer window, with this date set as October 5, 2020."
On Wednesday UEFA said the intention was for the group stages of the 2020-21 Champions League and Europa League to start in week beginning October 19.
England's top two tiers are to play out their remaining matches, with the Premier League campaign having restarted on Wednesday.
Forest will return to action on Saturday at Sheffield Wednesday and have nine games remaining.
