The 28-year-old topped up his match fitness by playing for Munster in their Magners League defeat to Cardiff last Saturday, scoring a try in the process. But did he expect to get back into the Ireland team so quickly after his recovery?
"No, not at all. I was just hoping to be involved (this weekend), hoping to be in the 22. It was something that I didn't think would be happening three or four weeks ago.
"I consider myself very lucky to be in the 22 and very lucky to be starting because Donnacha (O'Callaghan) and Micko (Mick O'Driscoll) have been playing well. Micko's been playing excellently all year so I consider myself very lucky to be playing," he said at the team hotel in Killiney.
O'Connell got a massive cheer when he came on as a second half replacement for O'Driscoll in the Scotland game. So how did he feel about the crowd's reception? "I was more concerned with the lineout because I could see they called a lineout. I was trying to get over as quick as I could and get on top of that but it was great to come on and get a big roar, especially at Croke Park."
Explaining the type of back injury he had, the Munster captain said: "I just had a small bulge on a disc. It's something that's been there for ages but never caused me any problems. It just inflamed and I couldn't get a grip of it.
"Eventually when I did, it was fine. But it kept causing problems. I was kind of caught in the middle in terms of, you know, sometimes if you've an injury that's bad enough, you get a job done on it and you get a timescale and you know when you can come back.
"I was lucky that my injury wasn't bad at all. Sometimes you would be thinking: 'will I just get a job done on this and give myself a time-frame then, something I can work towards?' But it was never that bad. The doctors kept saying that it (surgery) wasn't an option really."
Missing out on Ireland's first two Six Nations games and also Munster's crusade through the Heineken Cup's pool stages proved particularly frustrating for O'Connell, for whom rest was a key element in getting him back on the pitch.
O'Connell's appetite for training is well-known, with his Munster team-mate Anthony Foley famously admitting before the 2006 Heineken Cup final: "At times I've had to ask Paulie to tone it down in training - not so much for his own sake as the other fellas around him. They just can't do what he can do."
With the nature of the injury, O'Connell required plenty of rest and without his fix of daily training and a set date for his return, he admittedly found it tough to cope with at times.
"It was the kind of injury that when it went, it went two or three times. The physios were saying: 'look you could wake up in the morning and you'll be fine.'
"Then I'd wake up in the morning and it would be a lot better but not good enough to do anything. And they'd say you have to take another two weeks and two weeks later I'd be back on the road again.
"I've had several injuries but they've all been a case of you get your diagnosis, you're told six weeks and you're told you can do this training, this training and this training and you can use it to your benefit and work on different things. Whereas (with this injury), I was kind of going from week to week and that was frustrating," he added.
"With your back you can't do a lot - you can't do weights, you can't do speed (work) - all you can do is sit and relax and try and make it better and heal itself. That was the frustrating part of it, not knowing and not having a time-frame."
O'Connell heaped praise on the Munster and Ireland physios who did 'everything possible to get the injury right and make sure it wouldn't go again' when he got back playing.
"I've had a nice rest from the game, I suppose. I'd like to have more 80 minutes under my belt - there's no doubt about that - but I feel good.
"I've enjoyed the few bits of involvement I've had with Munster, Munster 'A' and Ireland. I've had a very enjoyable few weeks. I'd like to have more match fitness but that's an ideal world. I'm lucky in that I have a good natural fitness and I'll be calling on that (against Wales)."
The big second row has enjoyed plenty of battles with Wales over the years and he recalled making his debut against them in 2002 - "I ran into one of the Quinnells' elbows and got knocked out! I played on for about half an hour and scored a try but I don't remember it."
With the right result, the 2008 meeting of Ireland and Wales should be a match O'Connell remembers for a long time to come.