Evans, 22, has not played a minute's rugby since suffering a dislocated shoulder scoring a try for the Ospreys on December 28 that required reconstructive surgery.
He had been due to return to action against England in Wales' first warm-up Test but damaged his collarbone in training and was forced back into rehab again.
But after endless hours in the gym, Evans has been named on the bench for the Japan game and is determined to repay the coaches' faith in him.
"When I first got injured it was inconceivable that I'd be here in France," Evans said.
"It's been a long road but I've finally got here. The worst thing about being out injured is training by yourself in the gym, away from all your team-mates. It's a lonely world.
"After 10 months I'm sick of the sight of the gym. I am probably in the best shape of my career. I'm ready to play some rugby.
"Obviously there is some pressure to repay the coaches for the faith they have shown in me but I have no doubts about myself whatsoever."
Evans made his Wales debut on the same 2006 tour to Argentina as James Hook, who will start at inside centre in a much-changed Wales team.
Head coach Gareth Jenkins, hamstrung by a five-day turnaround and injuries to centres Gareth Thomas and Sonny Parker, has made 10 changes following the defeat to Australia.
Stephen Jones will captain the side from fly-half while Hook will partner Jamie Robinson in the centre.
Wales came in for a barrage of criticism following Saturday's 32-20 defeat and they must beat both Japan and Fiji next week to qualify for the quarter-finals.
Hook said: "We need a big win over Japan and that will take us into the Fiji game. Thursday is a must-win and hopefully we will then go into the Fiji game with confidence.
"We have a talented bunch of boys. This is not panic stations. Australia are six places above us in the world rankings and we didn't do bad really."