Roberto Bautista Agut (ESP) or Dusan Lajovic (SRB)
Round: Third Round
Marcos will compete in his first tour-level event since January when he steps on the clay courts of the TEB BNP Paribas Istanbul Open.
Marcos, who has competed in Davis Cup and at the Taipei Challenger in recent weeks, is returning to the ATP World Tour following an ankle injury. He opens against fifth seed Viktor Troicki in the first round on Tuesday. It will be their seventh meeting, with Marcos owning a 4-2 advantage.
Also in Marcos' half of the draw are potential second-round opponents Nikoloz Basilashvili and rising star Karen Khachanov, fourth seed Paolo Lorenzi and top seed Milos Raonic, who looms large in the semi-finals.
Marcos is making his debut appearance on the clay of Istanbul. The tournament is in its third year on the ATP World Tour.