When Celtic signed Moussa Dembele from Fulham in 2016, few might have predicted that the French striker would go on to become one of the most in-demand strikers in European football just four years later.

The forward left the West London club in 2016 to join Celtic, with the Scottish side forced to pay just £500,000 in compensation for the Frenchman despite him having already made 64 appearances for the Cottagers, in which he had contributed an impressive 19 goals and nine assists (per Transfermarkt).

He enjoyed two years with the Bhoys, in which he would make 94 appearances in all competitions, scoring an impressive 51 goals, whilst providing 18 assists for his teammates (per Transfermarkt).

Fulham's decision to let him go already looked a poor one when he joined Olympique Lyon for £19.7 million in 2018, as not only had the Cottagers missed out on a fairly-prolific striker, they had also missed out on what could have been a hefty transfer fee for Dembele.

However, in his two years with Lyon he has arguably progressed even further, having contributed 44 goals and 13 assists for Les Gones, which has proved enough to attract the interest of plenty of sides from across Europe.

We have seen the striker linked with a move to Tottenham Hotspur, Barcelona, PSG and West Ham in recent times and it perhaps seems unlikely that he will be with Lyon for much longer.

It is unsurprising to see how Dembele has progressed in recent years, as during his time with Celtic, his teammate Leigh Griffiths praised him heavily following a 4-0 win against Rangers, saying:

"With that display, Moussa showed he is one of the top young talents in Europe.

"He bullied their centre-halves and he was unplayable, and his penalty just summed the guy up.

"It doesn't matter how big the occasion is, he is always calm. I thought he was exceptional. He never gave the Rangers defence a minute's peace. He has that in the locker and when he is in the mood like that he is a joy to watch." (per Sports Mole)

Considering Fulham's poor form this season, which has seen them win just once in the Premier League, it could definitely be argued that they would benefit from a striker of Dembele's quality.

Therefore it seems as if it was a huge mistake by Tony Khan to not do everything he could to keep the Frenchman at Fulham back in 2016.