Robertson signed a two-year, $6.5 million contract with Pittsburgh on Tuesday, Elliotte Friedman of Sportsnet reports.
Robertson had been headed for an arbitration hearing, but it seems the two sides were able to work out a deal. In 78 regular-season games with the Leafs last year, the 24-year-old winger notched 16 goals and 16 assists, reaching the 30-point threshold for the first time in his career. For now, Robertson can likely be penciled in for a third-line role, but he could move up the lineup later in the year.