Sean O’Brien decision needs to be made after very worrying sight

This was so unfortunate to see.

Max Deegan is an Ireland international in waiting and Peader Timmins is apparently flying it for Leinster 'A' but Jordi Murphy's imminent departure to Ulster may be regretted yet. Sean O'Brien has played four times for Leinster this season and is half-way to matching his 2016/17 total. There is a chance that Leo Cullen and Stuart Lancaster may have opted to place him on the bench before Rhys Ruddock's unfortunate hamstring tear took that decision out of their hands. O'Brien was shifted from open- to blindside for the visit of Exeter Chiefs to Dublin but it was pretty evident that he was not 100%. Far from it. Leinster were blown away in the opening half hour, at the Aviva Stadium. O'Brien was not only struggling to stem the tide, he was struggling to get about the pitch. Seeing him grimace, curse, and strike his legs - as if willing them to respond to his demands - was a disconcerting sight. He was rarely seen as an attacking force in that first half but, then again, few of his teammates could say the same thing. 32 minutes in and a frustrated O'Brien barrelled into a Leinster ruck with an overly aggressive clear-out. Referee Pascal Gauzere had a brief word put play rolled in and the Frenchman was soon occupied with something else. It was a reminder that O'Brien, in fact, was on the pitch. Up until that point he had made three metres on three carries and most of his tackles were occurring around the corners of Exeter rucks. It was dogged but he was not slamming the door shut, like he so often does. The first half ended with Leinster clawing on and with their back row strangely subdued - 11 carries for 12 metres and unable to counter the Chiefs' hell-fire and brimstone. As the half-time whistle sounded, you just knew O'Brien. Josh van der Flier and Jack Conan would find a way back. You knew Exeter couldn't keep that pace up. You hoped that you knew anyway. O'Brien, warrior that he is, was much improved for the first 17 minutes of the second half. Leinster were too. He made five more carries, four more tackles and got himself involved in a rabble-rousing bust-up - backed up by Fergus McFadden and Tadhg Furlong - with several Exeter forwards. There was one sight that showed how Exeter had spotted him as a weak link and one to be attacked. Sean Cronin's lineout throw was claimed and popped to O'Brien at the back. The intent was to carry hard and get on the front foot. Don Armand and Mitch Lees pounced on him and dragged him, kicking and flailing, back three metres and dumped him to the turf. It was unceremonious and emphatic. O'Brien dusted himself off and, minutes later, made a strong carry up the left flank but that was it. His body caught up with him. He stretched his calves, received treatment, played on, made a carry that gained a yard, made a clear-out stretched his calves again, and cursed it until there was a break in play. [caption id="attachment_144567" align="aligncenter" width="500"] Credit: BT Sport[/caption] Leinster were replacing their entire front row, on 57 minutes, when O'Brien gave up the ghost and limped off. He looked as pissed off then as he did for much of Ireland's November win over Argentina. He is clearly playing whilst carrying a knock, or two. Following his side's 22-17 victory, Cullen said:

"Seanie had been carrying a knock coming into the game so I thought he did well to get through the minutes that he did. He's a great leader for the team as well so it's just about making sure we take care of him over the next little while. Try get him freshened up because he takes a heavy load, does Seanie."

That is the big decision Leinster need to make and one that won't be taken lightly. The Blues have a 9-day [playing] break ahead of their December 26 visit to Thomond Park and a clash with Munster. Following that, they have Connacht and Ulster at home in more Guinness PRO14 action. The wise course of action may be to withdraw O'Brien from the festive fray and leave him to see out the Champions Cup pool stages in mid January. We are dealing with a world-class player here but one that needs his game-time managed carefully if we are to draw every last bit from the tank.