Nyorai kuenderera mberi kweiyi ndima - O'Brien akadzoka kubva mukukuvara pamberi pemwaka wa2015 / 16. Akaratidza Connacht mumutambo wavo we preseason vachipesana neGrenoble, uye akaitwa kaputeni weEagles divi. MunaNovember 2015, O'Brien akatumidzwa muConnacht squad parwendo rwekuenda kuguta reSiberia reKrasnoyarsk kumutambo we2015 <unk> 16 Challenge Cup. Akaita kutanga kwake mukuru musi wa14 Mbudzi mumutambo wakanangana neEnisey-STM, achiuya mushure memaminitsi makumi mashanu nemasere achitsiva kaputeni John Muldoon. O'Brien akaita mutambo wake wekutanga mumakwikwi masvondo maviri gare gare mu2015 <unk> 16 Pro12
derby neMunster, achibuda pabhenji nokuda kwaEoghan Masterson sezvo Connacht yakakunda paThomond Park kokutanga kubvira muna 1986. Muna Ndira 2016 zvakaziviswa kuti O'Brien akasaina chibvumirano chevakuru nechibvumirano, icho chinomuona achiva nhengo yechikwata chakazara chemwaka wa2016 / 17.