After making one of the most expensive squad overhauls in recent history, Chelsea took some time to get going before hitting their stride.Following a 2-0 reverse to reigning Premier League champions Liverpool, Chelsea embarked on a nine-game unbeaten run that saw them challenge for the top spot in the league table.However, in an expected slide of sorts, the Blues lost four of their next six games to slip to ninth in the 2020-21 Premier League. Chelsea's dip in fortunes has a lot to do with the underwhelming returns of a plethora of players. Five Chelsea players who have flattered to deceive this seasonDespite the impressive early form exhibited by new goalkeeper Edouard Mendy and the exploits of Olivier Giroud, Chelsea have failed to arrest their downward slide since mid-December.The Blues slumped to defeats against Everton, Wolves, Arsenal and Manchester City and face a battle to qualify for the top four. So, without further ado, let us have a look at five Chelsea players who have largely failed to get going this season.#5 N'Golo KanteN'Golo KanteN'Golo Kante has been one of the standout players for Chelsea since arriving from Leicester City four years ago.However, the diminutive Frenchman has struggled to hit his stride this season, and that has had an effect on Chelsea's performances, especially in the Premier League.Kante has only impressed in bits and parts this campaign and is 'nowhere near good enough' as described by former Manchester United player Gary Neville.N'Golo Kante against Sheffield United:◉ Most recoveries (11)◉ Most tackles (5)◉ =Most interceptions (2)◉ 1 assistDoing what he does best. pic.twitter.com/CM5AALARcT— Squawka Football (@Squawka) November 7, 2020Neville's comments assume significance in light of Kante's horror show against Manchester City. The Frenchman appeared listless in his tackles, was exposed on too many occasions as a lone holding midfielder and appeared too slow to track back.#4 Mateo KovacicMateo KovacicMateo Kovacic has largely failed to light up Stamford Bridge with his performances since his arrival from Real Madrid two years ago.The 26-year-old midfielder has tallied a dismal two goals and seven assists in over 100 games for Chelsea in all competitions, a tally that comprises of only two assists in 20 games this season.Despite being the club's Player of the Year last season, Kovacic has struggled to get going in Lampard's 4-3-3 formation this campaign, as the Croatia international is not a quintessential number eight or a defensive number six.An honest assessment from the boss. pic.twitter.com/8DI4tL7Ub4— Chelsea FC (@ChelseaFC) January 4, 2021Unless the Chelsea manager returns to a 3-4-3 or a 4-2-3-1, which he is unlikely to do so any time soon, Kovacic's frailties would continue to get exposed, and the beleaguered Blues would be worse off for it.