Henson had been targetting a Welsh comeback in the Championship which kicks-off against England on February 4.
But the 2005 British Lion limped off the pitch during his side's 43-20 loss to Leinster , after making a 35 minute appearance off the bench.
Saracens were left counting the cost of their heavy defeat with a mounting injury list.
"Following Saracens Heineken Cup match against Leinster on Saturday, a number of the squad were injured during the game," read a statement on their website.
"Gavin Henson (calf tear) and Michael Tagicakibau (hamstring tear) have both been ruled out for three weeks.
"Hugh Vyvyan sprained his ankle and will be missing for two weeks while captain Steve Borthwick will have a scan later today on a shoulder injury.
"David Strettle left the field midway through the second half but has been given the all clear and there is also good news with Chris Wyles who returns after missing the last month with a fractured cheekbone."
Wales coach and 2009 Lions forwards coach Warren Gatland names his Six Nations squad on Sunday and has already lost Gethin Jenkins, Richie Rees and George North while he is sweating on the fitness of Adam Jones.