When scoring one of Ireland’s many tries against Italy at the weekend, the Leinster back Henshaw landed awkwardly on his shoulder and appeared to be in visible discomfort.
The 24-year old has undergone surgery on the shoulder, and will not take part in the remainder of the tournament.
His replacement is being touted to be Chris Farrell, regular starter for Munster.
Farrell, also 24, has appeared twice for his country before, against Fiji and Argentina.
The ex-Ulster youth product would make his Six Nations debut against Wales in Dublin.
In addition to his two caps for the senior team, Farrell made nine appearances at under-20 level, as far back as 2012.
Farrell moved to French Top 14 outfit Grenoble in 2014, where he played three years of rugby, playing 74 times and scoring 50 points.
The Belfast-native is yet to score for Ireland through those first two appearances.