O'Brien is running out of time to play any part in trophy mission
Sean O'Brien is losing his race to be fit in time for Ireland's remaining two Six Nations games against Scotland and England, after Leinster confirmed that the 31-year-old would not play for them this weekend.
Following Saturday's win over Wales, Joe Schmidt insisted that O'Brien was "on the cusp" of returning for Leinster against the Scarlets on Saturday but the province have moved to quickly dampen those expectations.
O'Brien hasn't played since suffering a hip injury in the Champions Cup win over Exeter back in December. There was significant enough damage caused for the Tullow flanker to require a small procedure and, while he will almost certainly miss the Scotland clash, his chances of making the Twickenham showdown look slim.
O'Brien has begun running, but has yet to partake in any contact work. He will be monitored.
Backs coach Girvan Dempsey commented: "Seanie did a volume of running last week, which is good, and we're pleased with his progress."