Dean Smith confirmed after Brentford's 2-1 win over Celta Vigo in their final pre-season friendly that Sergi Canos had rolled his ankle in the first half.
The Spaniard went in for a challenge and came off worse and, although he tried to run it off, he was unable to continue with Florian Jozefzoon replacing him.
Canos left the ground in a protective boot and will be a doubt for the season opener against Sheffield United.
He said: The early diagnosis is he rolled his ankle. He tried to carry on so it couldn't be too severe.
“We'll assess it and see where he is during the week. He looked really bright in the first half. It's obviously the biggest blow of the game so he should be all right.”
Smith, though, was delighted with the performance against the Spanish side, who were beaten in the Europa League semi finals by Manchester United last season, as they rounded off their campaign.
The head coach added: “You could see the quality they have on the football. Their head coach worked at Barcelona. We coped very well with it.
“The first half was a great game of football. There was low defending from both teams and it was hard to get through and it took a sublime pass from Josh McEachran to set up Lasse Vibe who took his goal very well.
“To go two goals ahead was very pleasing. I thought we passed the ball well at times.
“I didn't think we started the second half well and they showed their quality. When we made the subs we looked better and finished the game well. It's pleasing to get the result on the back of it.”
