Henson - who took an 18-month break from the sport - has been slowly finding his feet with Sarries.
But with less than a month to go before Wales' opener against England at the Millennium Stadium, Henson admits time is now running out.
"I need to be starting for Saracens to be in the Wales squad," said Henson. "I was hoping it would be in time for next month, but I am running out of time.
"Wales can win the Six Nations this year. They have definitely got the players and the game to do so. This could be our year."