It has been a miserable last 12 months for the 25-year-old lock who was tipped as a future British Lion during a rampant World Cup campaign.
Troubled by an on-going groin injury that should have been dealt with far sooner than it was - which Sidoli accepts part blame for - his fall from grace has nevertheless been as perplexing as it has frustrating. Since returning from Australia, he has started just once for Wales in their Six Nations defeat in Ireland last February.
During that time came the bitterness over the collapse of his beloved Celtic Warriors, the ensuing uncertainty and subsequent pressure of a high-profile move to the Blues. Proof that it never rains but pours when you are down.
"It's been a very frustrating year to say the least, probably one of the hardest in my career so far. It's easy to blame the injury but that wasn't everything. There were other factors that I had to get straight in my head," revealed Sidoli. "It took me a while to get back on track for the Celtic Warriors after the World Cup and again when I arrived at the Blues. I spoke to a few people who I respect because I needed to know why I was
starting so slowly and they helped me a lot. Most of them just told me not to push things.
"The move to Cardiff came with a lot of expectancy because of the size of the club and a lot of frustration because I knew I wasn't fully fit. It made things more difficult and was really getting me down.
"There was some confusion as to whether or not I needed an operation or not but in the mean time I was desperate to make a good impression at a new club. I was excited by the challenge but perhaps I was trying too hard and doing too much. When I realised this, things started to get better. I feel as if things are settled now."
They certainly are if last weekend's man-of-the-match performance against Gloucester was anything to go by. A commanding display at the lineout combined with a masterful performance at the heart of the Blues pack, evoked memories of the role he played with distinction for Pontypridd and will have had coach Dai Young beaming with satisfaction.
It will have undoubtedly pleased Wales coach Mike Ruddock as well having kept Sidoli in camp during the Autumn Series despite not featuring on the pitch.
"Mike was pretty honest and told me that I was pretty lucky to even be in the squad for the Autumn Internationals given the form of the other second-rows. Guys like Luke Charteris came through, Michael
Owen was used in the second-row and the move to France has obviously done Gareth Llewellyn a power of good," said Sidoli. "It might sound strange but even that was good to hear. It was nice to know that I was still in people's minds and just being around the rest of the guys helped my confidence.
"I used the time positively and took the chance to make up for the lack of a proper pre-season. I worked and trained hard and now I feel a lot better for it."
Sidoli's slump has been endemic of the Blues failure to find any consistency whatsoever. It is a symmetry that the Blues hope will continue given his apparent revival in form and, more importantly, confidence.
"Gloucester is a tough place to go and play but we were all confident in the potential that is here at the Blues. They had been tipped to win by a hundred points which was something that you just don't like to hear," said Sidoli. "Perhaps we had a point to prove and we responded but at the day we still lost and that was very disappointing. It's going to be another big challenge this weekend."
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Warren Gatland and Sam Warburton look ahead to this week's crunch RBS 6 Nations tie against France, where the Wales skipper in particular is keen to make his mark, as Paris has proved a bleak place for him in the past.
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WRU TV go behind the scenes with the Wales squad as they put the final touches in place ahead of the clash against Scotland at Murrayfield. Follow the squad on their captain's run, the kickers visit to Murrayfield and Neil Jenkins' press conference