Ronald Koeman was sacked 16 months into a three-year contract at Everton.
Ronald Koeman's failure to inspire his struggling Everton players probably cost him his job, says former England defender Michael Ball.
The Toffees sacked Koeman after a 5-2 defeat by Arsenal on Sunday left them third-bottom of the Premier League.
Ex-Everton defender Ball played under Koeman at PSV Eindhoven and said his man-management style was problematic.
"When results go bad he doesn't seem to know how to improve and lift players," Ball told BBC Sport.
"Ronald is great when things are going well. He's very blunt and painfully honest sometimes, but when you're getting results it's OK.
"When things aren't going well he struggles with his mannerisms. You never get a pat on the back - some players rise to that treatment and others, rightly or wrongly, can't deal with it."
Everton sack Koeman - reaction and debateAnalysis: Where has it gone wrong for Ronald Koeman? Michael Ball (right) played for Everton between 1996 and 2001
Koeman changed personnel and formation increasingly as his side's results have worsened, something Ball believes added to the problem.
"Under pressure you need to figure out a style of play and work on getting better at it, but he never had that this season," he said. "You could never second-guess his team or how they would play.
"Against Arsenal he was playing a right-sided midfielder in centre midfield and the game before that he had a right-back, Cuco Martina, at left-back.
"Everton were easy to play against. Whoever comes in now, even if it's temporary, will be able to improve things just by having a consistent way of playing and using players in their right roles."
Ball, who made 139 appearances for boyhood club Everton and won one England cap under Sven-Goran Eriksson, signed for Guus Hiddink's PSV in 2005.
The club won the Dutch league during his time in the Netherlands, but he was frozen out by Koeman when he replaced Hiddink in July 2006.
"I wanted Ronald to be a success when he came to Everton," said Ball. "I had my doubts because of my experiences playing under him but I wanted to be proved wrong.
"Seventh was a good finish after that first season but this summer the transfers became a problem.
"They did some good early work in the window but then it slowed and [Romelu] Lukaku went without being replaced. That's not just down to Koeman - the board need to hold their hands up for those failures too."
Source: bbc.com