Ulster Rugby player Craig Gilroy has apologised "unreservedly" for sending a "totally inappropriate" WhatsApp message in June 2016.
Craig Gilroy has made 160 appearances for Ulster.
He has also been capped for Ireland 10 times.
Some newspapers named him as the person who sent a sexually explicit message that came to light in the recent trial in which players Paddy Jackson and Stuart Olding were acquitted of rape.
Ulster Rugby and the IRFU have confirmed that he is subject to an internal review and will not play this weekend.
On Tuesday evening, he published a message on Twitter saying he was "deeply sorry for the hurt [his] message had caused".
"I would like to apologise unreservedly for any offence caused by the WhatsApp message I sent in June 2016," he posted.
"I would just like to clarify that it was sent privately, not part of any group chat.
"Regardless, my comment was totally inappropriate and is not an accurate reflection of my beliefs or Ulster Rugby's values.
"I take full responsibility for my actions and in future will ensure the language I use in private or public better reflects who I am and what I stand for."
A former pupil at Methodist College Belfast, he attended the high profile trial of his Ulster teammates.
During the trial, the prosecution referred to a particular WhatsApp messaging service exchange between Stuart Olding and a friend.
The message, to Mr Olding, contained a graphic sexual reference. At the time, Mr Olding's friend was only referred to by his initials - CG.
After the trial, some newspapers named CG as Craig Gilroy.
In a statement, Ulster Rugby said: "Ulster Rugby and the IRFU confirm that as Craig Gilroy is subject to an internal review, he will not be available for selection this weekend."
This announcement means that Ulster Rugby will now be without three of its most prominent players - Paddy Jackson, Stuart Olding, and Craig Gilroy - in Saturday's PRO14 game against Edinburgh.