Henson, who recently split from partner Charlotte Church and their two children, still has one year remaining on his contract at the Liberty Stadium outfit.
But with rumours that the star centre will be named in the latest series of Strictly Come Dancing, the Ospreys have not included him among their 47-strong player list.
Henson was also absent for the team photo for the 2010-11 season and was nowhere to be seen when the Ospreys launched their new kit on Thursday afternoon.
"It is significant that Gavin is not named among our squad on the website," said an Ospreys source.
"He appeared among our players all last season. But, at the moment, he has not been named in our Magners League squad to start the season next month.
"And we don't expect that to change when we name our Heineken Cup squad in the end of September."
Henson's last appearance for the Ospreys came against Gloucester in an Anglo-Welsh semi-final defeat, leaving him two games short of a century for the Swansea-based region he helped win two Magners League titles.