Well, he started as a SC Braga defensive midfielder. He was very young at the time. Very disciplined, he was a great marker and very hard working.
He then went to Benfica and he blossomed under Camacho. Playing with Petit in the midfield, the skinny anchor man started playing as a box to box. And he started to score on a regular basis, showing very good off the ball movement and great passing ability.
I still remember his press conference at Benfica when he said something like "It's great to be at a massive club. I'll try to learn as much as I can. I'd like to step in to another greater club, but I don't think that will happen...I may not be able to evolve that much".
Then Mourinho took him to Chelsea. Wasn't first choice, but played a role in the title winning team. Next stop Lyon, the once humble fellow wanted more football. And he just went to another level, playing with Juninho by his side.
Always showing great ability to score and to distribute.
Next stop was Juventus. Very negative year, but still regarded as the great mistery of italian football. I'd say Ranieri was the one at fault, but that's just me.
If he finds his feet, he'll gain his place back in the national team easily.