Tournament organisers say they are considering "all possible fixture permutations" following opening-round postponements in the European Champions Cup and Challenge Cup competitions.
England international Toby Flood has commended "a fantastic show of solidarity" by four-time European champions Toulouse after they paid an emotional tribute to the Paris terror attack victims.
Dan Biggar led Ospreys to a 25-13 win over Exeter at the Liberty Stadium as the Chiefs became the first English side to register a defeat in this season's European Champions Cup.
Simon Zebo scored a late try to secure a bonus point for Munster as they beat Benetton Treviso 32-7 at Thomond Park in their opening European Rugby Champions Cup game.
The European Rugby Champions Cup game between Racing 92 and Glasgow Warriors has been postponed - as have the other European matches in France this weekend - in the wake of the overnight attacks in Paris which left more than 100 people dead.
The European Champions Cup returns this weekend as players and clubs from all over the northern hemisphere look to put their disappointing Rugby World Cup campaigns behind them.
The pools for the 2015/16 Champions Cup were drawn last week and whilst a lot of things can change between now and the start of the competition later this year, it looks to be the most competitive European tournament yet.
Next season marks the second year of the new European competitions, and following the draws this week, Mike Stanton analyses the lay of the land for the European Champions Cup.
Bath and Wasps will be facing defending champions Toulon and Irish heavyweights Leinster in next season's Champions Cup after being drawn in a tough pool.
Two tries from Darren Dawidiuk and Jonny May in the last five minutes of extra time gave Gloucester a 40-32 win over Connacht and a place in next week's Champions Cup play-off final.