Jenkins, a Lions tourist in 2005 and 2009, is due to undergo surgery on a toe problem which has been cause of calf injuries that have blighted him over recent seasons.
He was limited to just one start in last year's Six Nations and made just four international appearances in 2010.
The 30-year-old is sidelined until April and will miss the Six Nations as well as some crucial Magners League encounters.
But he could be in line to return in the crunch Magners League clash at the Liberty Stadium against the Ospreys on April 1.
"It's a big blow for Wales and ourselves," said Young. "No one wants him to miss the Six Nations but it's better for him to have the operation now and be back before the end of the season for us and in time for Wales' warm up matches in the summer and the World Cup.
"Wales and ourselves have gone down every path, reducing his training and giving him longer rest periods because he wanted to avoid having an operation. But we have got to a stage where surgery the only feasible option.
"He's been frustrated because he hasn't been able to do the fitness work and training he would have liked and he feels it's affecting his game.
"It's important that we get Gethin back because we all know what he can do when firing on all cylinders."
Guinness PRO12
Suite 208, Alexandra House,
The Sweepstakes
Ballsbridge, Dublin 4, Ireland