It's very difficult to explain what has happened to Renato Sanches over the last season and a half.
Not only did he become the youngest player to win the European Championships in 2016 with Portugal, he was picking up individual accolades too, triumphing in the prestigious Golden Boy award.
So, when he moved to Swansea on loan for the current season, it came as a shock to all but those who had been watching him at Bayern Munich.
Carlo Ancelotti had failed to see what all the hype was about and handed the midfielder just six Bundesliga starts.
If further proof was needed that the 20-year-old's career is at an utter standstill, then take at his performance in the 1-0 defeat to Chelsea.
There can't have been many more abject displays in Premier League history, or at least it's hard to remember many - it was genuinely that bad.
One moment summed it up perfectly. Attempting to deliver the ball to a team-mate, he coolly passed it to the advertising hoardings.
His mishap sent Twitter into hysterics, with many fans suggesting he thought the red Carabao Cup logo was a Swansea away shirt.
However, on Match of the Day, Danny Murphy seemed to genuinely think that was a fair explanation for this ridiculous moment of ineptness.
"You see the red sign that he hits, that's what he sees in the corner of his eye because he thinks the left-back is moving back a few yards," he said, via WalesOnline.
"People might laugh at this, but it's true. The only reason I know is that I've done it a few times myself.
"Why would he pass it to nobody? It's the same colour as the shirt, it's not a coincidence. I've done it a few times, trust me!"
We're sure you have Danny, we're sure you have.
The more appropriate response was that of Paul Clement, who looked absolutely despondent on the touchline, putting his head in his hands.
The Swans boss must be giving serious thought as to how he can reinvigorate the former Benfica man, while his team now sit joint bottom of the table with Crystal Palace on nine points.
Will Sanches ever fulfil his promise? Have your say in the comments.