 On the day before his first game for the Lions, O'Brien signed with the Ottawa Redblacks of the CFL on May 31, 2014.O'Brien was placed on the exempt list for the PIFL, and began the season as the third QB on the Redblacks depth chart.A season-ending injury to second-string quarterback Thomas DeMarco allowed O'Brien to see action during the 2014 CFL season.