Xavi was "in a state of shock" following news of former Barcelona star Dani Alves being arrested on suspicion of carrying out a sexual assault.
Brazilian right-back Alves was arrested in Barcelona on Friday after it was alleged he assaulted a woman in a nightclub bathroom.
The 39-year-old denied committing the offence when he spoke to Spanish broadcaster Antena 3 in early January.
Alves, who has also played for Paris Saint-Germain and Sevilla, gave a statement to the Mossos d'Esquadra police force on Friday before the public prosecutor's office requested that he should be detained and not granted bail.
He has been kept in prison while investigations continue, and his contract with Mexican club Pumas UNAM has been terminated.
Xavi, a former Barcelona team-mate of Alves, signed the defender for a short second Barcelona stint last season.
Speaking in a Barcelona pre-match press conference on Saturday, Xavi said: "It is difficult to comment on a situation like this. I am surprised, shocked, in a state of shock.
"It is a matter of justice. Justice will dictate whatever."
Alves became the oldest player to feature in a World Cup match for Brazil when he played against Cameroon in Qatar last month.