Marcos has received a main draw wild card for the China Open, an ATP World Tour 500 event. The site of his first tour-level title (in 2006), the tournament in Beijing holds a special place in Marcos' heart.
Looking to replicate the success from his victory 12 years ago, he will kick off the week against eighth seed Marco Cecchinato. It is their second meeting, with the Italian previously taking a clay-court encounter in Bucharest in 2016.
Should Marcos advance, he will face the winner of Andreas Seppi and Marton Fucsovics. Top seed Juan Martin del Potro, fourth seed Fabio Fognini and seventh seed Borna Coric are also in his half of the draw.
Main draw play begins on Monday.