Eurosport - Pablo Piatti, left (Reuters)
The 23-year-old Argentine was taken to hospital and would remain there for 48 hours, the club said.
Valencia have made a slow start to the campaign under new coach Mauricio Pellegrino and lie 17th in La Liga with two points from three games.
They have been drawn in Champions League Group F along with Lille, BATE Borisov and last year's finalists Bayern Munich, whom they visit for their opening game in two weeks' time.
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