Chile midfielder Charles Aranguiz faces a lengthy injury lay-off after tearing his Achilles tendon, just a week after joining Bayer Leverkusen, the Bundesliga club announced on Friday.
The 26-year-old tore the ligament in his left ankle in training on Thursday evening and faces an operation in Basel, Switzerland, next Tuesday.
He will be out for months and is unlikely to play again this year.
The Copa America-winner was on the bench for Leverkusen's 2-1 win at home to Hoffenheim last Saturday and had been due for his Bundesliga debut at Hanover on Saturday having only signed for the German side from Brazil's Internacional on August 12.
"We've all been hit hard by the news and we're all suffering with him," said Leverkusen's director of sport Rudi Voeller.
"We will do everything we can so that Charles comes back as quickly as possible from this bad injury."
Aranguiz, a defensive midfielder, is reported to have cost Leverkusen 12 million euros (US$13.3m) and had been brought in to boost the German club in the middle after the departure of Germany internationals Gonzalo Castro and Stefan Reinartz and also the retirement of Simon Rolfes.