Dan Sheehan at number eight: why Leinster’s Munster experiment is about more than carrying power

Dan Sheehan’s move to number eight gives Leinster a way to start two international hookers against Munster. Whether it improves their pack will depend on the less conspicuous parts of his new job as much as anything he does with the ball.

Rónan Kelleher starts between Andrew Porter and Tadhg Furlong on Saturday, with Sheehan joining Ryan Baird and Josh van der Flier in the back row. Our confirmed Leinster and Munster team news sets out the full selections.

The immediate circumstances are clear. Caelan Doris is unavailable and Jack Conan’s shoulder injury has removed another established number eight. But Leo Cullen’s explanation suggests this is also an opportunity to test an idea Leinster had already considered.

An injury response with a longer history

In comments reported by The Irish Times, Cullen said Leinster had discussed the switch towards the end of last season and had already tried it briefly.

“It’s very early in the season still, so it’s worthwhile us trying some things,” he said.

That matters when assessing the selection. Injuries have created the opening, but Cullen is also using the depth available at hooker. Kelleher starts, Sheehan remains in the pack and Gus McCarthy provides front-row cover from the bench.

The potential benefit is straightforward: Leinster can field Kelleher and Sheehan together without asking either to share the starting hooker’s minutes. The cost is that Sheehan must take on responsibilities usually handled by a specialist number eight.

The scrum is the clearest change

Sheehan already carries, tackles and works at the breakdown as a hooker. Changing his shirt number does not introduce those demands.

The base of the scrum is a more distinct adjustment. Controlling the ball with his feet, keeping it available when the scrum moves and judging when to release or pick up possession are central parts of the role.

Those details will shape the quality of ball reaching Jamison Gibson-Park. A clean exit would allow Leinster to move quickly into their attacking shape; untidy possession could give Munster time to close the space.

That makes scrum exits a useful measure of the experiment. A powerful carry later in the same passage would not erase an avoidable delay at its beginning.

Two tries at Clermont do not settle the question

Sheehan arrives after scoring twice in Leinster’s 48-23 Champions Cup win at Clermont.

Those scores demonstrate the attacking contribution Leinster already receive from him at hooker. They do not, by themselves, show that moving him to number eight will produce more.

The relevant comparison is the whole pack. Does adding Kelleher allow Leinster to sustain their carrying and support work while preserving control at the set piece? Can Sheehan fulfil his new duties without losing the involvements that make him valuable in his usual position?

A try would be welcome. It would answer only part of that assessment.

Cullen expects defensive continuity

Cullen also told The Irish Times that hookers and number eights can occupy similar defensive positions in Leinster’s system.

That is an important qualification to the idea that Sheehan faces an entirely unfamiliar assignment. The coaching staff expect some of his existing responsibilities to transfer.

It does not establish that every decision will be the same. His starting position after a scrum changes, and his coordination with the flankers and scrum-half will need to hold up when possession becomes untidy.

For Munster, the obvious opportunity is to make those transitions difficult. Their confirmed team includes Gavin Coombes at number eight, Alex Kendellen and Jack O’Donoghue on the flanks, and Craig Casey at scrum-half.

What would make the experiment a success?

The strongest evidence would be a pack that functions smoothly with both Kelleher and Sheehan on the field: controlled scrum possession, clear defensive organisation and effective support around the ball.

Even then, one derby cannot establish Sheehan as a permanent number eight. Leinster are selecting around injuries, and the balance of the pack will change when their absent players return.

Saturday can answer a narrower, useful question: whether Sheehan gives Cullen a credible additional back-row option while allowing Leinster to use their strength at hooker.