And while he hasn't been able to break into the Ireland starting XV, Lions head coach Warren Gatland's desire to take more than one genuine No7 to Hong Kong and Australia meant the 28-year-old was still in the running for place on the plane.
Henry was on the bench for Ireland's opening win in Wales and Round 2 defeat to England but he won't play any further part in the Championship after picking up a knee injury on Friday.
The six-times capped back rower tore cartilage in his right knee during Ulster's bonus-point win over Zebre at Ravenhill, with an Irish Rugby Football Union statement confirming he will be sidelined for 'approximately four weeks'.
That length of absence would see him miss Sunday's clash with Scotland in Edinburgh, the March 9 tie with France in Dublin and the following week's trip to Rome, although he would at least return in time for Ulster's Heineken Cup battle at Saracens on April 6.
The news is yet another blow for Ireland coach Declan Kidney, who is already without tournament starters Jonathan Sexton, Cian Healy, Gordon D'Arcy, Simon Zebo and Mike McCarthy, while there are still doubts over the fitness over Brian O'Driscoll and Donncha Ryan.
Lions trio Paul O'Connell, Stephen Ferris and Tommy Bowe haven't played any part in the tournament and are unlikely to do so.
Munster's uncapped Tommy O'Donnell replaces Henry in the 30-man squad that met at Carton House last night but it would be a surprise if won an immediate call up to the bench this weekend.
Connacht centre Dave McSharry's failure to overcome the groin injury he suffered in last week's win over the Ospreys has forced another reshuffle to the squad, with Leinster's Ian Madigan called up just a day after appearing to have missed out to Ulster's Paddy Jackson in the race to be Ronan O'Gara's back at Murrayfield.
Rory Best (Ulster), Darren Cave (Ulster), Tom Court (Ulster), Seán Cronin (Leinster), James Coughlan (Munster), Keith Earls (Munster), Luke Fitzgerald (Leinster), Declan Fitzpatrick (Ulster), Craig Gilroy (Ulster), Robin Henshaw (Connacht), Jamie Heaslip (Leinster), Ian Henderson (Ulster), Paddy Jackson (Ulster), Rob Kearney (Leinster), David Kilcoyne (Munster), Ian Madigan (Leinster), Luke Marshall (Ulster), Fergus McFadden (Leinster), Conor Murray (Munster), Seán O'Brien (Leinster), Donncha O'Callaghan (Munster), Tommy O'Donnell (Munster), Brian O'Driscoll (Leinster), Ronan O'Gara (Munster, right), Peter O'Mahony (Munster), Eoin Reddan (Leinster), Mike Ross (Leinster), Donnacha Ryan (Munster), Lewis Stevenson (Ulster), Devin Toner (Leinster)