On September 25, 2015, Sean Payton announced that starting quarterback Drew Brees would miss the first game of his Saints career due to a bruised rotator cuff and that McCown would get the start on September 27 against the Carolina Panthers over rookie Garrett Grayson, marking McCown's first start since 2011 with the Jaguars. Luke's older brother Josh started for the Browns the same day, marking the first time the brothers both started since 2007. On November 5, McCown underwent successful lower-back surgery, effectively ending his season after he was placed on injured reserve. McCown completed 32 of 39 passes for 335 yards and an 82.1 completion percentage in 2015.