The race for the league title in England seems to be heading only in one direction, with Manchester City strong favorites to win the league at the moment. Although the competition for the Premier League has not been close, five clubs from England are still playing for glory in the Champions League.Every English club needs to get reinforcements to have a good chance to win the trophy, and the winter transfer window provides this opportunity to analyze and improve any weak positions. Fatigue has been a regular problem in the latter stages of the season as has been clearly evident with Barcelona in recent years. Hence, with the relative inexperience of English clubs to reach the last stages of the Champions League, managers need to be prepared for this problem by making effective buys in January.Let's have a look at the positions that require backup or replacements for England's top clubs, and the players that each club should try to sign:#5 ArsenalLacazette has fit in well at ArsenalPositions that need strengthening - Centre-back, Central Midfielder, Attacking MidfielderArsenal have had a topsy-turvy start to the season, lying in fifth place in the EPL table with 5 losses and 1 draw. They have been very unconvincing at times while being fantastic in other games.The appealing football that Arsenal is capable of playing was on show in an unfortunate loss to Manchester United last week, where they dominated proceedings. The 2-0 win against Tottenham a few weeks back was another high-profile game which provided the Gunners' fans plenty to cheer about.But inconsistency has meant that Arsenal are definitely not among the favorites to win the league title. Although they may already be out of reckoning to win the title, Wenger needs to build a strong team for the future and a step towards that would be by making significant acquisitions in January.The first issue to be addressed are the contracts of Alexis Sanchez and Mesut Ozil, with the players looking likely to leave either in January or the summer. If the players do leave, they will definitely need replacements of the highest calibre to fill their massive voids.Assuming the players won't leave, the positions that Arsenal need to strengthen are centre-back and central midfielder, attacking midfielder/winger. The Gunners' defence was torn apart earlier this season in a 4-0 loss at Anfield, and defensive mistakes cost them dearly against Manchester United as well. The need for another centre-back is of utmost importance with the pairing of Koscielny and Mustafi being highly unconvincing.Koscielny has been extremely important in the last few years holding the defence together, but with rumors suggesting that he might be looking for a move back to France, Arsenal need to replace him with a defender of the highest quality.A ball playing centre-back would be a boon, and with rumors of an offer for Kalidou Koulibaly (Napoli) doing the rounds, Arsenal fans will be hoping the transfer goes through. His strengths include precise passing and tackling, which are very similar to that of Koscielny's strong attributes and hence could be a like for like replacement.Kalidou Koulibaly could prove to be a vital signing for the GunnersSince the era of Cesc Fabregas, the position of controlling central midfielder has never been filled successfully. Santi Cazorla's long-term injury has meant that there is no single midfielder to dominate the middle of the park.Someone in the mould of Barca legend Xavi or Real Madrid's Toni Kroos is required, in order to regain the lost spark in midfield. Jean Michael Seri (OGC Nice) has been linked to Arsenal constantly, and with the master Xavi himself praising Seri's Barca-esque possession-based football, he is an exciting controlling midfielder that Arsenal must target.Another player who has been perennially linked to Arsenal is Leon Goretzka (Schalke), a 6'3'' tall midfielder who has all the attributes required to flourish at Arsenal. Goretzka is a free agent next summer, so Schalke maybe be looking to sell him at a small fee in January itself.“I did not know him and I was stunned: I haven’t seen such midfield talent for a while. [His] short game, long game, tactical intelligence, distance shooting, personality, game organisation…wow!” - Xavi on Jean Michael SeriAnother requirement for Arsenal is someone to support Sanchez and Ozil in the final third of the pitch. Ramsey has not been upto the mark this season, and Ozil has regularly been accused of disappearing in major matches. PSG's Julian Draxler has been sidelined at his club after Neymar and Mbappe's entry, and this could leave the door open for him to join Arsenal. At the age of 24, he still has his peak years ahead of him and could turn out be a worthy signing for the Gunners.Draxler was linked with a move to the Emirates in the past