Better news for boss Josef Schmidt is that centre partner Brian O'Driscoll has been passed fit after his injured knee held out in the Heineken Cup final.
There remain doubts over scrum-half Isaac Boss' hamstring though and Schmidt admits it's far from ideal preparation for the final.
"We have a couple of injuries and Gordon won't be available for selection," said he said.
"He hurt his ankle in the Heineken Cup and has been ruled out.
"There are a couple of others with niggles but hopefully they will come through. Isaac Boss isn't looking in great shape and is also a doubt.
"There's an air of expectation and hopefully we can replicate our second half performance against the Saints.
"But no disrespect to Northampton, I cannot see Munster giving us as many opportunities. Especially at Thomond Park Munster will have a lot more resolve and will be difficult to break down.
"Northampton were tired, maybe it was the cumulative impact of a long season, but Munster won't offer us those opportunities in attack."