But the Gloucester and Wales back-rower has pledged to be fitter and stronger than ever before following his return to action against London Irish on Saturday.
Delve, 26, said: "I've got a lot of unfinished business. I set my ambitions out at an early age and I've assessed them every time I've picked up a knock.
"I still think I'm capable of achieving every one of them. I have got a fantastic family and girlfriend behind me and they have helped me pick up the motivation whenever I have faltered or wondered if it was still all worth it.
"From my point of view it certainly is. You just have to take these things on the chin."
The latest knee injury on Wales' tour to South Africa last summer, on his already reconstructed left knee, was a bitter blow to his chances of returning to the republic with the Lions later this year.
Delve had earned the right to make only his second start for his country against the world champions in June - but lasted just 23 minutes before rupturing his cruciate ligaments.
"What doesn't kill you makes you stronger - that's the adage I live by and I just try to come back better," added Delve, who has been capped nine times by Wales.
"The last time I got a major injury, I thought nothing could go wrong again. But these sort of things have a habit of creeping up on you just when you least expect it.
"I had reached the last game of last season and was looking forward to a good pre-season and moving on from there.
"It was fantastic to be a part of the Welsh set-up last year. Once I get fit and well I will be looking to be a big part of it again and cement a place in the starting line-up.
"You either find out if you've got it or not when you have injuries like these. I would obviously have preferred not to have had them and have 50-odd caps in the cabinet now, but that's not how it has turned out.
"Every time you have to go back to the well and re-motivate yourself and say I really want this.
"I can still make a difference and get back out there and do it. I've managed to miss two World Cups through injuries so it would be great to finally make it in 2011.
"I know I can't afford to set my sights too far ahead and the first step is to get back out on the field for Gloucester. I want to show people what I am still capable of.
"I know I can come back from this and show people I am a better player than I was."
Delve admits he can't wait to get the chance to re-pay the faith shown in him by his club.
"Joining Gloucester last season was just the fillip I needed. It was a fresh start and a new challenge.
"It rankles with me that I haven't been able to contribute anything this season. The back row resources have been stretched this season and at times we've been down to only three or four fit.
"I'm really keen to finish off the season with a bit of silverware. We got close last season but, after picking up the Grand Slam with Wales, I was desperately keen to transfer that to my club form.
"I have been hankering to play full stop. I can't wait to get out there and pull on the Gloucester shirt and give something back to the club."