Leo Cullen is set to conclude his 12-year tenure as Leinster's head coach at the end of the current season. This campaign represents his final chance to lead the team to a fifth title, having previously captained them to three and coached them to a fourth.
In other European rugby developments, Toulouse has secured the signing of centre Tommaso Menoncello. Bordeaux has also strengthened their squad by bringing in Tom Willis.
Meanwhile, Cheslin Kolbe has returned to South Africa, joining the Stormers. He is part of a star-studded group that includes Siya Kolisi and Wilco Louw, alongside existing Springboks such as Damian Willemse, Sacha Feinberg-Mngmezulu, and Cobus Reinach.
Northampton Saints' Fin Smith is anticipated to have a significant season, having regained his position as England's fly-half. Sione Tuipulotu is also expected to be a key player for Glasgow Warriors in their Champions Cup campaign, following their quarter-final appearance last season.