Wales wing Steff Evans has been ruled out of the two-Test series against Argentina with a knee injury.
Evans was forced off during the win over South Africa in Washington on Saturday and the Welsh Rugby Union confirmed the player's worst fears have been realised.
The WRU said in a statement: "Steff suffered a knee injury against the Springboks which precludes him from taking any further part in the summer tour.
"He will return to Wales for further investigations to establish an accurate diagnosis and prognosis."
Worcester wing Josh Adams has been called up as replacement for Evans, while Tomas Francis has also joined the squad as cover for Samson Lee, who is battling a lower back injury.
Wales opened their summer tour with a 22-20 victory over the Springboks, Ryan Elias grabbing the decisive try with seven minutes remaining after Robert du Preez's clearing kick was charged down by Tomos Williams.
They face Argentina in San Juan on Saturday, with the second Test taking place in Sante Fe on June 16.