Tullow Tank ready for Henry 'havoc'
O'Brien knows his side are up against it
Sean O'Brien is the man in possession of the Ireland jersey held by Chris Henry last season.
The Tullow Tank has known his share of injuries, the rickety shoulder having to be stabilized twice before O'Brien could truly recover his powers of physical persuasion just in time for the latest Six Nations.
Around that time last year, O'Brien was having to deal with an infection into his original reconstruction which caused a loss of his place, a loss in weight and, eventually, a second operation.
All the while, Henry was putting what former Leinster coach Joe Schmidt liked to call his "nuisance" value to proper use for Ireland as they captured the 2014 Six Nations championship.
"Chris is one of those players who will be involved in everything," said O'Brien.
"He's always around the tackle area. He stays in the middle of the ruck the whole time. He's one of those lads that just don't go away.
"He and Rory (Best) are very similar like that at the breakdown.
"They cause havoc by staying in the ruck a lot and we'll be looking to get them out of there as quickly as possible."
Of course, Henry had to handle the experience of waking up to a mini-stroke on the morning of Ireland's November international against South Africa, his room-mate Rhys Ruddock having the presence of mind to call for medical assistance immediately.
The Ulster flanker, describing the incident as "terrifying," had to have surgery for a hole in his heart and worked his way back to an earlier than expected return for Ulster against Cardiff Blues as a replacement just over three weeks ago.
He followed this with a start against Connacht at The Sportsground last Saturday week.
"It's great to see him healthy again. It could have been different.
"He's a massive threat. He's back now. He's eager. He's fit again. It's going to be a big evening.
"The problem is solved. It's like any injury or illness. It's great to see him back and it's another option for Ireland leading into a World Cup year."
There is a fair argument to suggest it all starts here. The holder versus the challenger, a heavyweight contest.
This is just one of a number of head to heads that should enthral on Friday. Sean Cronin and Best is another. Jared Payne and Ben Te'o too.
These are mere sub-plots that could have a significant impact. The more likely scenario is that it will come down to the collective.
Leinster do not have any room for wriggle. They are a long way from fourth place (eight points). They have to win all three remaining games with at least two bonus points to hold out any reasonable hope.
"That's what we have to do. We're fighting for our lives," he stated. "We have to give ourselves the best possible chance at the end of these three games. It starts this week. Everybody is aware of that.
"We're not hiding from that or glossing it over it. We're in this position now.
"We've let a few games slip during the year which we shouldn't have. And we're going to have to find our way out of it."
Interestingly, O'Brien points to a "lack of voice, lack of leadership" due to injury and the Player Welfare priority of Ireland over the provinces.
In fact, he was speaking ahead of what will be just his second League outing for Leinster this season.
"Definitely, that is one of the factors that, when there are a lot of the key players missing, everything feels a lot quieter.
"On the other hand, you have guys like Jack McGrath and Jordi Murphy who have all gotten their first taste of the level that is required and they are future leaders."
At the moment, the only time that matters is Friday night.