 On 22 October, Markström earned his first NHL win when he played in the third period against the New York Islanders and made 18 saves on 18 shots.Markström started the lockout shortened 2012–13 season in the AHL, but with the starter Jose Theodore suffering an injury on 2 March that forced him to miss the rest of the season, Markström was given the de facto full-time role, starting most of their games during the remainder of the season.It was believed that Markström would become the full-time starter for the Panthers at the beginning of the 2013–14 season, as Theodore was not retained and Markström signed a two-year contract extension.