Naby Sarr joined Charlton Athletic in July 2015, a highly-rated France Under 21 defender with bags of potential.

On paper, he looked to be a superb acquisition, a player with a big future who needed regular matches rather than stagnating in a big club's reserve side.

He had served his apprenticeship at Lyon and later Sporting Lisbon, never breaking through but always showing lots of promise. He played Under 20 football for his country, then appeared twice for the Under 21 side.

He seemingly had the world at his feet, but after struggling to make an impact in Portugal, he wound up at Charlton Athletic.

His first season wasn't one he'd be writing home to his friends about. The Addicks were relegated from the Championship, dropping out of the top two divisions for the second time in eight years.

Sarr played 12 times and it seemed as though his career was over before it had begun at the Valley. In 2016/17 he was loaned out to Red Star, a French Ligue 2 side. To all intents and purposes, that should have been the end of his Addicks career.

He didn't do badly at all in his loan spell and when he returned to the club he found a route back into the first team. Since Lee Bowyer has taken over, he's become an integral part of the back four, looking calm and assured on the ball.

He's never reached the heights expected of him in his youth career and maybe League One doesn't offer the sort of test that he first expected, but this season he's certainly impressed. He's a strong presence at the back in the side fighting desperately for a place in the Championship.

Despite the warnings, false starts and patchy form, Naby Sarr is finally coming good at Charlton, almost four years after first joining the club.