Which Premier League managers fighting drop could face sack?

Everton's Roberto Martinez and West Brom's Tony Pulis saw their sides fight out a goalless draw on Monday

Only six points separate the bottom nine sides in the Premier League, and the pressure is increasing on the teams battling to stay in the top flight.

Two of the teams in trouble, Crystal Palace and West Brom, have changed their managers this season - but who else is at risk?

BBC Sport takes a look at what the managers who are fighting the drop have done at their clubs so far, and the tests they face next.

And chief football writer Phil McNulty gives his verdict on who is safe and who is under threat.

Everton - Roberto Martinez

Martinez was relegated from the Premier League when he was manager of Wigan in 2013

Lowdown: Had a superb first season in succession to David Moyes, taking Everton to fifth in the Premier League in 2013-14, and back into Europe with their highest-ever points tally. This season, however, has been a more of a struggle - the Toffees are yet to record back-to-back victories in the league and have never been higher than ninth.

Form: LDLWL LLLDD

Upcoming games: Crystal Palace (a), Liverpool (h), Chelsea (a)

Did you know? Everton have gone eight games without a win in all competitions and have won only one of their last 13 matches.

Phil McNulty's verdict: "Struggling in the bottom half of the table, Martinez has also had to face questions from fans over what they see as an occasionally ponderous passing style. This is the same man, however, who did such a superb job last season - Everton chairman Bill Kenwright is a loyal, patient man who will remember that." Job security: SAFE

Crystal Palace - Alan Pardew

Pardew has been relegated only once as a manager - when Charlton dropped out of the top flight in 2007

Lowdown: Has only just started his reign at Crystal Palace after deciding to leave Newcastle, and has three wins out of three games so far - following an FA Cup victory at Dover by coming from behind to beat Tottenham and then Burnley.

Last 10 games: DLDDL LDDWW

Upcoming games: Everton (h), Leicester (a), Newcastle (h)

Did you know? Pardew has won more points from losing positions (16) than any other Premier League manager this season.

Phil McNulty's verdict: "The rejuvenated Pardew appears to have tapped into the spirit and desire that Tony Pulis invoked when Palace survived last season. Sacked? He's only just got there." Job security: SAFE

West Brom - Tony Pulis

Pulis has never suffered relegation as a manager

Lowdown: Kept Crystal Palace up in style last season and has been brought to The Hawthorns to repeat that feat. Has made a strong start to his new job by taking five points from his first three league games.

Form: LLDWL LLDWD

Upcoming games: Tottenham (h), Burnley (a), Swansea (h)

Did you know? Pulis has lost only one of his last 10 matches as a Premier League manager (W6 D3).

Phil McNulty's verdict: "Pulis is much more than a firefighter, as his excellent time at Stoke City proved - but his job at The Hawthorns is to avoid relegation, and there is more of a feeling of wellbeing around West Brom since the man who has never suffered the drop replaced the sacked Alan Irvine.

"Pulis is his own man who will do it his way - and if West Brom leave him to it, they will survive." Job security: SAFE

Aston Villa - Paul Lambert

Lambert led Norwich to back-to-back promotions before taking charge at Villa

Lowdown: Lambert has survived two relegation battles since taking charge of Villa, and is now facing a third despite a good start in which they were second after taking 10 points from their first four games.

The goals have dried up as they have slid down the table and, with Villa the lowest scorers in the top flight with just 11 goals in 22 league games, Lambert's tactics have been heavily criticised by fans. Some have called for him to be sacked and there is also unrest among supporters about the direction of the club with chairman Randy Lerner unable to find a buyer.

Form: DWWLD LDDLL

Upcoming games: Arsenal (a), Chelsea (h), Hull (a)

Did you know? Villa have only scored 97 goals in 98 games in Lambert's regime.

Phil McNulty's verdict: "Lambert might be cut some slack if Villa at least showed signs of revival but 522 minutes without a goal tells its own story.

"The pressure is growing on him and defeat at home to AFC Bournemouth in the FA Cup fourth round on Sunday could be a tipping point. Bear in mind, though, that he signed a contract extension until June 2018 at the start of the season - and who would take the job or do better in the current inertia?" Job security: UNDER THREAT

Sunderland - Gus Poyet

Poyet kept Sunderland up last season and also took them to the League Cup final

Lowdown: Took charge in October 2013 with the Black Cats bottom after taking just one point from their first seven games, and kept them up. Has made them hard to beat this season, and picked up plenty of draws, but a shortage of wins means they have never got clear of trouble.

Form: DLDDW LDLLL

Upcoming games: Burnley (h), Swansea (a), QPR (h)

Did you know? Poyet has picked up more points from draws (11 points) this season than from wins (nine points).

Phil McNulty's verdict: "Gus Poyet has great credit in the bank but they are once again sailing in dangerous waters this season - although owner Ellis Short clearly believes in his manager after giving him the money to secure the signing of Jermain Defoe. Short, however, has shown he is not afraid to take the ruthless decisions.

"Poyet is perfectly safe unless it looks like there may be another serious brush with relegation but the Black Cats must improve." Job security: UNDER THREAT

Burnley - Sean Dyche

Dyche has been in charge at only one other club - he was sacked by Watford in 2012

Lowdown: Steered Burnley to promotion last season, and is trying to keep them up without the spending power of his rivals. Took 11 games to earn his first Premier League win, but since then his side have climbed out of the relegation zone.

Even so, they have only spent a few hours higher than 17th place this season - when they beat QPR on 10 January, but saw Crystal Palace move back above them by beating Tottenham later in the day.

Form: DDLWL LDDWL

Upcoming games: Sunderland (a), West Brom (h), Man Utd (a)

Did you know? Dyche has named the same starting XI in Burnley's last eight Premier League games.

Phil McNulty's verdict: "Dyche is a hero among Burnley fans and hugely respected within the club. There is not a chance he will lose his job, even if they went back down." Job security: SAFE

Hull - Steve Bruce

Bruce experienced relegation with Birmingham in 2006 but took them back up to the top flight the next season

Lowdown: Won promotion in his first season, and reached the FA Cup final as well as securing safety in his second. So far, his third campaign in charge of the Tigers has been far more forgettable, with just four wins so far this season.

Form: LDDLL WLWLL

Upcoming games: Newcastle (h), Man City (a), Aston Villa (h)

Did you know? Bruce has seen his team take only 59 points since the start of last season, the lowest total of any ever-present Premier League team in that period.

Phil McNulty's verdict: "Hull need to find a way to turn some decent approach play into goals and wins. Abel Hernandez, a club record buy at £10m, has not delivered the goods yet and a loan deal for Hatem Ben Arfa did not work out.

"Bruce has shown his loyalty to Hull by turning down three offers in his time at the club - it is to be hoped owner Assem Allam reciprocates even if times get even tougher." Job security: UNDER THREAT

QPR - Harry Redknapp

Redknapp took QPR up via the play-offs last season

Lowdown: Took charge of QPR in November 2012 with the club bottom of the table and could not keep them up. Won promotion back to the top flight at the first attempt, but this season has been undermined by their dreadful away form - they became the first club in the Premier League era to lose their first 10 league games of the season on the road.

Form: WLWLW LDDLL

Upcoming games: Stoke (a), Southampton (h), Sunderland (a)

Did you know? Redknapp has the lowest win percentage of any permanent QPR manager in the Premier League (19%).

Phil McNulty's verdict: "QPR's drop into 19th place led to widespread speculation that Redknapp would be sacked if they lost to Manchester United - they lost but hardly played like a team that had lost faith in the 67-year-old.

"And now, owner Tony Fernandes has issued an unequivocal statement saying Redknapp will keep his job as he believes he is the best man to get them out of trouble. If Redknapp can get his side playing away from home like they do at home, he may repay his faith." Job security: SAFE

Leicester - Nigel Pearson

Pearson returned for a second spell as Leicester boss in 2011 after leaving to take charge of Hull in 2010

Lowdown: Took Leicester up as champions and initially prospered in the top flight, with the highlight a 5-3 win over Manchester United that sent the Foxes seventh. A winless run of 14 games followed and they slumped to the bottom of the table. But they have taken seven points from their last four games to regain touch with the teams above them.

Form: LLLLL LWDWL

Upcoming games: Man Utd (a), Crystal Palace (h), Arsenal (a)

Did you know? Nigel Pearson has seen his team put more clear-cut chances off target (14) than any other Premier League team this season.

Phil McNulty's verdict: "The odd shaft of light apart, this has been a season of struggle for Pearson and the fragile nature of a manager's relationship with fans was seen in his spat with a supporter for which he received a one-game touchline ban and a £10,000 fine for insulting a supporter.

"He has been backed with a club record £9m to sign Croatia striker Andrej Kramaric from FC Rijeka and needs him to deliver fast or the pressure will increase on the manager of the bottom club." Job security: UNDER THREAT