For the 2015 IndyCar Series season Briscoe had been in negotiations to race for Schmidt Peterson Motorsports, but that fell through when financial arrangements could not be made for the team to field a third car. However, the team then called Briscoe in as replacement driver for James Hinchcliffe at the 2015 Indianapolis 500 after Hinchcliffe suffered a severe injury after qualifying for the race. He returned to the team at Texas and joined as permanent replacement driver from Fontana onwards. He collected four top-ten finishes in eight races in what were his final appearances in the championship.