And he is not the first manager to do so in the Premier League.
Having been in charge at Watford for the 2015/16 season, Sanchez Flores will be only the sixth permanent manager to have two different periods in charge of the same Premier League team, when he oversees the visit of Arsenal on Sunday.
Guus Hiddink also had two spells in charge at Chelsea but both times was just an interim manager.
|Manager||Club||Last match of spell||Matches||Win %|
Sanchez Flores led Watford to a 13th-place finish in 2015/16, while steering their run to the FA Cup semi-finals.
He will be keen to improve on this, but history suggests it will not be easy.
Of the five permanent managers who have returned to a club, only Redknapp had a better win percentage in his second spell than his first.
And only Redknapp and Hiddink took charge of more Premier League matches after their return than they did during their initial spell.
Sanchez Flores will seek an immediate impact as he aims to secure Watford's first win of the season and lift them off the foot of the table.
But returning managers have had mixed results in their comeback match, with two winning, one drawing and two losing.
Coincidentally, Coppell and Kendall began their second spells with a match against each other. Coppell came out on top as Palace won 2-1 at Everton on the opening day of 1997/98.
|09/08/97||Coppell||CRY||Won 2-1 v EVE (A)|
|09/08/97||Kendall||EVE||Lost 2-1 v CRY (H)|
|12/12/05||Redknapp||POR||Lost 3-1 v TOT (A)|
|19/01/08||Keegan||NEW||Drew 0-0 v BOL (H)|
|18/08/13||Mourinho||CHE||Won 2-0 v HUL (H)|
|26/12/15||Hiddink||CHE||Drew 2-2 v WAT (H)|