Seán O’Brien won’t take risks with injury to play in Pro 12 decider against Ulster

“You smash buses, taxis and you smash people who come towards you,” explained Seán O’Brien. That’s a bit like rugby then? “Yeah very like playing a game,” he said.

It's what we've come to know and love about the Irish flanker. His part in a new mobile game Street Rugby allows people to control him as he tackles his way around the streets of Dublin.

It’s a fitting metaphor for O’Brien’s rampaging style and selfless physical contribution to all things Leinster, although yesterday his capacity for the hard yards remained doubtfully in the balance.

O'Brien will know this morning if he can play tomorrow. If he does Lions coach Warren Gatland was given the biggest bum steer this side of Alice Springs when he said his Irish pick should be fit for the second or third game of the tour.

Still, O'Brien's mood is buoyant and the tour, which shakes off all the other distractions on Monday when the Lions fly out to Hong Kong, opens up a summer of opportunity.

'Going to be tight'
"It's going to be tight. That's being honest," he said. "At the start of the week it (knee) was looking a little bit dodgy but then come Monday evening I was feeling very good again, I was feeling loose. I suppose if the next 24 hours are really good it will be touch and go I think.

“The fact is if I get another slap on the same spot where the bone bruising is it might hinder my chances of playing in the first couple of games on tour. That’s the risk and the danger. They’re going to assess it again tomorrow and see what happens.”

The decision will not be taken by the flanker. The fact it is a final tomorrow is a guiding imperative to the medical team, but caution often rules especially with the chance of O’Brien breaking down during the game and also ruling himself out of the Lions in a worst-case scenario.

“If I’m fit, I’ll play. If I’m not . . . there won’t be a risk taken, I’ll put it to you that way,” he said. “There’s no point in taking a risk at this stage. It will be touch and go.

“If it wasn’t for the Lions I’d probably just chance it because if anything did happen I’d have the rest of the summer to heal up. It’s a massive day for the club. It’s very important. That’s the thing that’s killing me the most, not knowing what way it will be and whether to chance it or not.”

It was a simple collision of two knees that caused the problem, although, when it happened first thoughts turned to his calf muscle, which had been a problem.

In a Leinster context, O'Brien is the only concern management have outside the long-term list of injuries, with back Fergus McFadden and hooker Richardt Strauss both expected to be available for Joe Schmidt in his last Leinster outing.

“That’s all it was, a freak thing,” O’Brien said with finality. “This is a fresh injury. I don’t pass the fitness in the morning then no big deal.”