Roberto Martinez
Roberto Martinez is under scrutinyGetty

Even though it was expected that Everton would become established in the Premier League elite during Roberto Martinez's second year in charge, the Toffees are struggling to replicate their impressive last season.

After a very poor run of six defeats in the last eight Premier League games, the boss needs to bolster the squad this January to overcome the situation – or may face an uncertain future at Goodison Park in the summer despite his promising start.

What they need:

After the signings of Romelu Lukaku, Gareth Barry and Samuel Eto'o the squad looks long and versatile but the results say the opposite.

The forwards are struggling to prove their real worth but it is particularly on the back-line where the Toffees are having trouble, having conceded 31 goals in the first 19 games.

Furthermore Martinez may consider signing a goalkeeper after Tim Howard was ruled out for up to six weeks following the calf injury he sustained on Boxing Day.

Who could join:

Martinez may take advantage of his knowledge of Spanish football once again to find a bargain in La Liga. Because of this, the Toffees have been linked with Barcelona right-back Douglas and promising starlet winger Adama Traore.

Meanwhile, Everton are reportedly likely to secure a cut-price deal for Marseille striker Andre Ayew as the Ghanaian's contract at the Ligue 1 side runs out in the summer.

Manchester United youngster Adnan Januzaj and Dinamo Zagreb's Marcelo Brozovic are also said to be on Martinez's radar to bolster the midfield.

Who could leave:

James McCarthy has been linked with a January move to Arsenal but Martinez himself recently claimed that having paid Wigan Athletic £13m for him just at the start of last season he will be at Goodison Park for "a long, long time".

The manager also ruled out the possibility of Kevin Mirallas moving away, despite some reports linking the Belgium international with Liverpool.

Meanwhile right-back Seamus Coleman is said to be being monitored by Manchester United.

What the manager has said:

"Transfer windows are always opportunities to see if we can find anyone who can fit in well at the football club and help the players that we have.

"But I don't see the January transfer window as a window that we need to buy players to be able to perform well and get the results. The solutions can be found internally but obviously we will always look at the window to see if we can take advantage of any opportunity."