His decision throws a possible return to rugby into even greater question, with his commitments to the series expected to last until the New Year.
The 28-year-old had said earlier this week that he was targeting a place in the Wales squad for the 2011 World Cup but this latest development appears to make that goal even more unlikely.
But while Henson has not been included in the Ospreys squad listed on their official website for the current season and hasn't featured for the region since March 2009, director of coaching Scott Johnson stressed that the door has not been closed on their prodigal son.
"I had one conversation with Gavin a year ago but he has not spoken to me since. The situation is exactly the same as before," said Johnson, who coached Henson while with Wales.
"As I keep saying, the door is still open for Gavin to come back and talk as we respected his wishes at the time.
"From the start, I have paid him the courtesy to acknowledge his wishes - I'll continue to do that.
"People can ask me the question about Gavin. But only when he comes through my door and we re-ignite our conversation then I will answer.
"But, at the moment, I will pay him the courtesy of his privacy as that's where we were a year ago.
"From that, the conversation sits where it sits and I will acknowledge where he is when he comes back."
Henson was today unveiled as the figurehead of the international advertising campaign for the new Wales kit, with his image set to be plastered over buildings, on television sets and in newspapers over the coming weeks.
His return to Welsh colours is just the latest development in a long-running saga that still seems no closer to being resolved.
Henson made no attempt to hide his pride in being back in a Wales shirt but, for now at least, he looks set to make do with modeling the new kit rather than wearing it an anger in an international.
"When the Welsh Rugby Union asked me to be one of the first to put on the new kit to help with their marketing campaign I had no hesitation," said Henson.
"As a passionate Welshman I have always felt a great sense of pride whenever I have had the privilege of being able to wear the national jersey and this occasion was no different.
"I've never been to a Rugby World Cup which is coming up in 2011 and I'm thinking about training for that.
"Hopefully I can get back into rugby, do well and get into the World Cup squad. It's the one thing that is not on my CV."