It is the latter he finds himself for what will be his maiden European start, following a previous bench appearance against Racing 92 in Le Havre. He had been named at outside centre in the team Cullen had hoped to field away to Montpellier in December 2021, before the Blues were ultimately forced to concede a 28-0 walkover to the Top 14 outfit.

“He’s very accomplished. Since he’s come into the team he’s been a really key performer for us. He’s played at 12, 13 and a little bit at 15. He has a big left foot, he’s nice and strong. He’s athletically improving all the time and he’s much more confident in himself,” Cullen explained in a video call from Gloucester yesterday.

“Going away for the St Stephen’s Day game [against Munster] he put in a really big performance that day, which is great to see. One fantastic offload where he gathers the ball, is able to hold off the defender and get the ball away for that Luke McGrath line break.

“Defensively, he’s very solid and sound as well. He’s one for the future, definitely. He’s still very young, but he’s an important player for the squad now over the last while.”

While he more than merits a spot in the first 15, Osborne’s inclusion from the start is partially brought on by some notable absentees. Ireland international Robbie Henshaw has been sidelined with a wrist injury for several weeks and Charlie Ngatai is also ruled out courtesy of a hamstring issue that led to him being withdrawn at half-time in last weekend’s URC victory over Ospreys.

Additionally, James Lowe has travelled back to New Zealand for family reasons and misses out on facing Gloucester for a second time in the current campaign. Lock Joe McCarthy (ankle) is also sidelined, though Cullen expects him to be available for next weekend’s showdown with Racing 92 at the Aviva Stadium.

Whereas Cian Healy is in line to become just the fifth player to make 100 European appearances if he’s called upon off the bench, his fellow replacements Michael Milne, Brian Deeny and Liam Turner feature in a Champions Cup match day squad for the very first time.

In comparison to their 57-0 demolition of the same opposition in the RDS just over four weeks ago, Leinster are anticipating a much tougher task from Gloucester on this occasion. George Barton and Ben Meehan are the only survivors in the English Premiership side’s starting line-up from that chastening, with former Ireland U20s hooker George McGuigan amongst those added to the mix.

Although dealing with a drastic change in personnel is a major challenge in itself, Cullen identified another factor that could make this round three affair a difficult proposition for his charges.

“It’s more probably the occasion, being away from home. The crowd, ‘The Shed’ and how they back their team. It’s just making sure we’re nice and clear. When we were away in Wales last week against Ospreys, we’ve had some changes from that game as well,” Cullen said.

“I think the guys that were over there understand that away from home, that mentality is slightly different for us. A great challenge, really looking forward to it.”

GLOUCESTER: G Barton; J May, C Harris, S Atkinson, O Thorley; S Carreras, B Meehan; V Rapava-Ruskin, G McGuigan, K Gotovtsev; F Clarke, M Alemanno; R Ackermann, L Ludlow, B Morgan.

Replacements: S Blake, H Elrington, C Knight, C Jordan, J Clement, S Varney, B Twelvetrees, T Seabrook.

LEINSTER: H Keenan; J Larmour, G Ringrose, J Osborne, J O’Brien; R Byrne, J Gibson-Park; A Porter, D Sheehan, M Ala’alatoa; R Molony, J Ryan; R Baird, J van der Flier, C Doris.

Replacements: R Kelleher, M Milne, C Healy, B Deeny, J Conan, N McCarthy, H Byrne, L Turner.