The Spanish defender was subbed out of Sunday's 3-2 win over West Ham United with a hamstring injury and suggests he may not be fit in time for Villa's visit to Anfield on Saturday.
"I am okay, but I don't know if I'll be ready for the game. It's nothing bad, but I don't know if I'll be able to play," he told the club's official website.
"I've had some treatment and then we will see. I hope I can be fit for the game."