The champions did kick-off with a win over their arch Irish rivals but coach Alan Gaffney prepares to face Llanelli Scarlets at Thomond Park on Friday night with plenty to ponder over.
"It is a real shame for Hendo and I am glad we will be at home for this one as the Scarlets will be a very difficult exercise, they are an extremely good side," said Gaffney.
"We have had a couple of great games against them and, in the last one, if it had been a boxing match, they would have won on points. They were the better side but just didn't get the rewards."
"We know that we face a real tough challenge against them and we expect a hugely competitive contest."
"We have got 12 players on international duty plus the loss of Hendo, so I guess we will be calling on some club players, but that was always on the cards at some stage."
"As far as the match against Leinster goes, let's just say it wasn't pretty - but we will take the win. When there are 36 penalties in a game you simply cannot have an enjoyable game for either players or spectators."
Besides the injury to Henderson, Gaffney also faces a problem at out-half after Jason Holland hobbled off in the course of the opening half. Holland had started the game with a heavily strapped ankle after he had suffered the injury in the game against Connacht a week previous. He was replaced by veteran Killian Keane who had been drafted into the side because Conrad O'Sullivan had also been ruled out through injury, again sustained in that Connacht game. It is likely that once more Keane will be pressed into action on Friday.
Munster will train in Cork on Wednesday where the side to play Llanelli is expected to be announced after the morning training session.
Tickets are now on sale for Munster v Llanelli in Thomond park on Friday Sept 12th at 7:30pm
Tickets are available from Musgrave park (9.30 - 5pm except 1-2pm) and tickets are available from Thomond park from 10am - 3pm. Tickets will also be available at the gate on the way in.