In the 2010–11 season Ronald started with top performances, scoring, among other goals, four braces against Westerlo, Charleroi, Zulte-Waregem and Standard Liège. Vargas continued his good form in the start of the second part of the tournament, but on 6 February 2011 he suffered an anterior cruciate ligament injury in a league match against KRC Genk, only eight minutes after the start of the match. He was expected to be out for over six months, missing the chance of playing with his national team in the 2011 Copa América.