Sunderland boss Steve Bruce became the first Premier League casualty of the season this week, and his firing may cause some other managers in the league to shift nervously in their hot-seats.
Bruce had led the Black Cats to a very respectable 10th place finish in the Premier League last season, but was axed after a run of two wins in 13 games this term.

Chelsea manager Andre Villas-Boas is currently not meeting expectations at Stamford Bridge, and if his struggling team do not pick up their form he could join a long list of managers to get the bullet from trigger happy owner Roman Abramovich.

Claudio Ranieri, Carlo Ancelotti and Avram Grant were all fired by Abramovich with Chelsea second placed in the Premier League, while Jose Mourinho was dismissed after winning two Premier League titles, and never losing a Premier League game at Stamford Bridge.

Given those facts, Chelsea’s current positioning of fifth place in the Premier League appears to leave the man known as AVB in a precarious position.

Villas-Boas now faces a crucial stretch of games before the turn of the year, with December seeing the Blues play six Premier League games and an important UEFA Champions League clash against in-form Spanish club Valencia.

This brutal December stretch will see Chelsea face three of the Premier League’s top four teams, and a Valencia team that have won their last two Champions League matches by a combined score of 10-1.

This weekend Chelsea travel to face fourth placed Newcastle United who drew 1-1 with Manchester United at Old Trafford last weekend. Chelsea’s next league game will then be a home game against unbeaten league leaders Manchester City.

Sandwiched between those two games is a crucial Champions League clash against Valencia with qualification for the knockout stages on the line.

Bayer Leverkusen beat Chelsea 2-1 last time out in the Champions League and gave themselves a one-point lead at the top of Group C. Chelsea and Valencia are tied for second place and are only one point behind Leverkusen.

If Chelsea beat Valencia they will guarantee themselves a spot in the last 16, a 0-0 draw will also see the Blues go through due to away goals in the head to head tie-breaker. If Valencia win or achieve a score draw, then Chelsea will be eliminated in the group stages of the Champions League for the first time ever.

The financial blow and loss of prestige that would accompany Champions League elimination is the reason so many fans and pundits fear for AVB’s job security.

If Villas-Boas can navigate that three game stretch, he will lead the Blues into road games at Wigan Athletic and third placed Tottenham Hotspur. The calendar year will then be rounded off with home games against Fulham and Aston Villa.

“For our Premier League to be alive we need to make the most of the December games,” Villas-Boas told BBC Sport this week. The Portuguese tactician then added that “in the Champions League this (current) standard won’t be enough.”

If Villas-Boas is to feel safe in his job over Christmas and New Year he must begin producing results. If not, the initials AVB could stand for ‘Another Vulnerable Boss.’