World Rugby has confirmed it will hold internationals in the Northern Hemisphere from October 12 until December 5, meaning Ireland will complete their Six Nations schedule before participating in an invitational tournament with other European sides and potentially Fiji.
The body has also agreed to hold the 2020 Rugby Championship in one host country - most likely New Zealand - from November 7 until December 12.
That could mean Munster will be without Springbok signings Damian De Allende and RG Snyman for the first round of the Heineken Champions Cup which is fixed for the weekend of December 12. Ulster could also be affected if Marcell Coetzee gets a South Africa recall.
Ireland are set to complete their Six Nations campaign against Italy at home on October 24 and France away on October 31, with the other unplaced matches going ahead on that day.
They will then get a weekend off, before playing in a once-off tournament involving the other Six Nations and two other teams, Georgia and Fiji, are expected to make up the numbers.
The format has not been confirmed, but it seems likely that the eight teams will be split into two groups of four with a final weekend on December 5.
The Irish provinces' return, meanwhile, will get under way with Leinster taking on Munster at the Aviva Stadium on August 22.
Guinness PRO14 organisers have confirmed the dates and kick-off times for the last two rounds of the truncated season that will see the four Irish provinces lock horns at Lansdowne Road.
The matches are likely to take place behind closed doors at first, with attendances currently limited to 200 people including participants and officials. Ulster take on Connacht on the opening Sunday, before they take on Leinster and the westerners face Munster a week later.
Leinster and Ulster are guaranteed their semi-final spots, but Munster still have work to do to book their spot and can top their conference ahead of Edinburgh who face back to back derbies against Glasgow.
All games will be within their own country, with Ulster the only team moving beyond their own public health jurisdiction for the first two weeks.
The PRO14 semi-finals on the first weekend in September will see the first matches between teams in different countries.
The final venue has not yet been set, while the fixtures involving the South African sides have not been announced and may not be played due to covid-19
GUINNESS PRO14 fixtures:
Friday, August 21: Bennetton v Zebre, 7.0
Saturday, August 22: Scarlets v Cardiff Blues, 3.0; Edinburgh v Glasgow Warriors, 5.15; Leinster v Munster, 7.35
Sunday, August 23: Ospreys v Dragons, 2.15; Connacht v Ulster, 4.30
Friday, August 28: Glasgow Warriors v Edinburgh, 7.35
Saturday, August 29: Dragons v Scarlets, 5.15; Leinster v Ulster, 7.35;
Sunday, August 29: Munster v Connacht, 3.0; Cardiff Blues v Ospreys, 5.0; Zebre v Bennetton, 7.0
Final Series - Semi-Finals: To be played on the weekend of September 4/5/6
Finals: To be played on Saturday, September 12