#4 Ex-Watford boss didn't rate him
During the winter of 2013, Arsène Wenger sent the highly-rated 18-year old on loan to Championship side Watford. In that time the Spaniard only made 8 appearances and many Arsenal fans couldn't understand the reason why. As it was clear the youngster wouldn't be getting the minutes he needed, Wenger recalled him after only two months.
A few years later, Watford captain Troy Deeney gave us insight into why the La Masia graduate played so few games at Vicarage Road. He revealed that the manager at the time, Giuseppe Sannino, found the Spaniard to be too lightweight in the tackle and not defensively suitable to play for his side.
It's safe to say that Sannino didn't rate the Arsenal defender in the slightest. After Wenger recalled the youngster that season, he played in a Champions League match away at Borussia Dortmund, where he had an appalling performance.
However, as with many things, Wenger was proven right about the quality of the Spanish defender. Bellerín now stands tall as one of the best young defenders in not only the Premier League but world football.
