#4 Bob Bradley

Swansea City were always the usual suspects when it came to relegation, but somehow managed to avoid it until the 2017-18 season.
But, they were very close to being demoted to the second division in the 2016-17 season, when they appointed Bob Bradley as their manager. Under him the club only managed two wins and conceded 25 goals in 11 games.
Bradley was sacked by Swansea after only 84 days, they managed to finish 15th that season in what can only be descried as a miracle.
#3 Frank de Boer

Frank de Boer, an excellent player himself for Ajax and Barcelona, had a forgettable spell in the EPL as a manager, as he failed to win a single league game in his short 77-day stint at the Selhurst park.
Under him Crystal Palace lost their first four league matches of the season without scoring a single goal, becoming the first team in 93 years history of the English top-flight competition to have begun their season in such a fashion.
His stint becomes the shortest of the Premier League era if the number of minutes he was in-charge is considered is considered, with just 450 minutes of PL experience on his CV.