#1: Marcelino
There must be something about midfielders that makes them tend to take up management. Pep Guardiola, Frank Lampard, Paul Scholes, Zinedine Zidane, Gennaro Gattuso and of course Allegri and Setien were all midfielders before entering the dugout. Marcelino is no different.
Of the three people on this list, Marcelino was the first to try his hand at management, starting in 1997, three years after retiring as a player. Between 1997 and 2005, he managed CD Lealtad, Sporting Gijon B and Sporting Gijon.
Marcelino does not stay for too long at a club but the longer he stays at a club, the better the side's defence becomes. In his 16 matches at Racing, his side conceded an average of 1.56 goals per game. In his 37 matches at Recreativo Huelva, it was 1.41 goals per game, and in his 59 game sin charge of Real Zaragoza, the team shipped 1.24 goals per game.
In his most recent job as Valencia manager, Marcelino managed 110 games, his second longest spell in charge of a club, which saw them concede just 0.97 goals per game on average.
With a career win percentage of 46.38% and a philosophy which relies on having a sturdy back-line with lethal forwards in front of them, Marcelino could be the person who helps Arsenal fix their leaky defence.