Mezue ahịrịokwu na-esonụ: O'Brien laghachiri mmerụ ahụ tupu oge 2015<unk>16. Ọ gosipụtara maka Connacht na egwuregwu preseason ha megide Grenoble, ma mee ya onye isi ndị Eagles. Na Nọvemba 2015, a kpọrọ O'Brien na ndị otu Connacht maka njem gaa obodo Siberia nke Krasnoyarsk maka egwuregwu 2015 <unk> 16 Challenge Cup. O mere egwuregwu mbụ ya na 14 Nọvemba na egwuregwu megide Enisey-STM, na-abịa mgbe nkeji 58 dị ka onye nnọchi anya onyeisi John Muldoon. O'Brien mere asọmpi mbụ ya ka izu abụọ gachara na
2015<unk>16 Pro12 derby megide Munster, na-abịa na bench maka Eoghan Masterson dịka Connacht meriri na Thomond Park maka oge mbụ kemgbe 1986. Na Jenụwarị 2016 ekwuputara na O'Brien abanyela nkwekọrịta nkwekọrịta, nke na-ahụ ka ọ bụrụ onye otu ndị otu egwuregwu zuru oke maka oge 2016-17.