Titus Bramble was released on bail after being arrested on suspicion of sexual assault and possession of a class A drug.
The former Ipswich, Newcastle and Wigan player was held for questioning by Cleveland Police following an incident in the early hours of Wednesday.
A spokesperson told the club's official website: "Sunderland AFC has confirmed that Titus Bramble has been suspended from duties, pending the outcome of a club investigation.
"The player will not attend team training or be available for selection for matches during this period.
"The club is unable to make any further comment on the matter at present."
