Valencia have begun disciplinary proceedings against their forward Rafa Mir after the 27-year-old player was arrested last week by the Spanish Guardia Civil police for an alleged crime of sexual assault, the club said on Monday.

While not officially disclosing the details of the disciplinary measures, club sources told Reuters the striker will be fined and removed from the rest of the group for an indeterminate period of time.

"Valencia wish to reiterate the club's firm condemnation of any violence in any form, while respecting the presumption of innocence that our legal system promulgates," the club said in statement.

"The justice system must decide the course of action regarding the allegations for which Rafa Mir is being investigated.

"However, as far as the club is concerned, and within the framework of its competences, we have analysed the situation and decided to undertake disciplinary measures.

"Specifically, the club will proceed to open a case against Rafa Mir as we feel his way of behaving, in his time off, indisputably affects the professional performance expected of him as a player of this club, damaging, in addition, the confidence that our fans have in all of the players.

"The club will continue to collaborate with the police in whatever way required."

Earlier on Monday, Mir denied having committed sexual assault and apologised for "failing to comply, even on a day off, with the rigorous timetable expected of a professional and even more so after a start to the season that fell short of our expectations."

Mir, who has also played for Wolves and Sevilla, was arrested last week after a woman filed a complaint against him, and he testified before a judge on Wednesday.

The judge who ordered his conditional release will now lead an investigation to establish whether there is enough evidence for Mir to stand trial or if the case should be dropped.

Mir will have to appear in court regularly and is not allowed to leave the country.

Information from ESPN's Sam Marsden contributed to this report.