The 24-year-old played 73 minutes for his native Uruguay in their 3-1 World Cup qualifying win over Chile last weekend, registering two assists and retaining his starting berth in attack for Tuesday night’s clash with Ecuador.
However, Nunez was replaced by Felipe Carballo at half-time of that 2-1 loss, with La Celeste head coach Marcelo Bielsa since revealing that the player has been having muscle issues as he explained why he was taken off at the break in Quito.
“Darwin arrived with some muscular difficulties and this limited his actions,” said former Leeds boss Bielsa.
“I thought it necessary to replace him because he worked too much trying to press and attack in the last game.”
Jurgen Klopp will hope that Nunez is able to shake off any lingering problems as Liverpool gear up for a return to top-flight duty after the season’s first international break on Saturday.
The Reds open the weekend with a lunchtime trip to face struggling Wolves at Molineux, sitting third in the early table behind Manchester City and Tottenham having made an unbeaten start to the campaign with three wins from four matches including the impressive 3-0 victory over Aston Villa at Anfield last time out.
The in-form Nunez had an important role in that win, with his first-half shot hitting the post and deflecting in off Matty Cash before he later teed up Mohamed Salah for the third goal after the interval.
Those contributions came after the former Benfica frontman, who has endured a mixed spell on Merseyside since his high-profile club-record £85million switch from Portugal last summer, came off the bench to net both goals in a dramatic 2-1 victory over Newcastle on Tyneside - a result achieved with only 10 men which Klopp described as among the greatest comebacks of his illustrious managerial career.
Klopp will be expected to provide a further update on Nunez’s fitness when he addresses the media ahead of the Wolves game on Friday, plus the likes of Thiago Alcantara, Trent Alexander-Arnold and Ibrahima Konate.
Captain Virgil van Dijk will sit out again this weekend after he was handed an additional one-match ban and a £100,000 fine by the Football Association (FA) after admitting that he acted in an improper manner towards match officials after his early sending off for a foul on Alexander Isak in the win over Newcastle.
Van Dijk already missed the win over Villa but will be eligible to return at home against West Ham on September 24, with Liverpool first facing a trip to Austrian side LASK in their Europa League group stage opener next Thursday.