Not fat per se, but his body fat looks to be above 11% - which is what they say footballers stay at during the season. Ronaldo for instance is sitting at 7% (as per his medical at Juve), most of our players - eye balling by the training pics look to be lower than 11% as well.
Arthur's upper body is very built but he has barely any definition, and, in my view, there's no need for an athlete to carry that extra weight. But then again, I don't know but going by the reports I cited above, the people at Barca who had a look at him seem to agree.
And you're right, I feel Luis would be better off emulating the physique he had as a youngster in the Eredivisie. Not meaning to bring up Ronaldo again, but I do vaguely remember reading that he had a team of Sports Scientists suggest he lost 1.5kg a year (after he turned 30) to maintain his athleticism to counter ageing. And he does indeed look slimmer than before.
