The Italian led the club to a remarkable Premier League title win last season but the 2016/17 campaign has seen their form collapse and Ranieri, this week, lose his job.
Here, we use WhoScored.com's stats-based rating tool, to compare the average rating for Leicester's players this season and last to reveal just how far below their 2015/16 level they are performing…
RIYAD MAHREZ - 7.84 DOWN 1.10 to 6.74
Mahrez is the Leicester player who has fallen furthest this season. The 2015/16 player of the year has scored three goals - all penalties - and recorded two assists. Crucial to their devastating counter-attacks in the previous campaign, at this stage last year the winger had 14 goals and 10 assists.
Image:Riyad Mahrez has managed just three goals and two assists this season
JAMIE VARDY - 7.51 DOWN 1.02 to 6.49
Leicester's 2-1 defeat in Sevilla was just the second game in the last 27 in which Vardy has scored.
He has not had a shot on target in the league since mid-December. With five league goals - having scored 19 at this stage in the previous campaign - Vardy's WhoScored.com rating is the second lowest of 101 outfield players to have started at least 20 Premier League games this season.
Image:Vardy had 19 goals at this stage in 2015/16
DANNY DRINKWATER - 7.30 DOWN .56 to 6.74
Drinkwater has remained one of Leicester's more consistent performers this season, but consistently average compared to last season.
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The England international has had to cover for the loss of N'Golo Kante's ball-winning ability - averaging more tackles per game (3.3) - to the detriment of his passing ability, with key passes down from 1.3 to 0.5 per game.
Image:Danny Drinkwater has recorded just one assist
CHRISTIAN FUCHS - 7.50 DOWN .56 to 6.94
It's not just going forwards that Leicester look a shadow of last season's title winners. They have kept just two clean sheets in the league since a 0-0 draw with Southampton at the start of October.
Fuchs' rating has fallen furthest of the defence after an excellent debut campaign, though his is still the best ranking by a distance of all Leicester players to make more than five appearances.
Image:Christian Fuchs has seen a significant drop-off in form
DANNY SIMPSON - 7.13 DOWN .51 to 6.62
With both tackles (1.7 to 1.1) and interceptions (3.1 to 1.8) down significantly this season, Simpson's displays have been underwhelming. As a result, his rating in the current campaign is the lowest of a back four that has remained unchanged.
Image:Danny Simpson is making fewer tackles and interceptions per game
ROBERT HUTH - 7.15 DOWN .48 to 6.67
Huth's partnership with captain Wes Morgan was pivotal to Leicester's success last time but it's fair to say their lack of mobility has been exploited this season. Without the protection Kante provided, both have struggled, with the German making more fouls than tackles this season.
Image:Robert Huth has made more fouls than tackles this season
WES MORGAN - 7.07 DOWN .42 to 6.65
Morgan has kept his record of playing every minute in the Premier League since the start of last season but with far less success this time out. His pass accuracy has dropped significantly (74.4% to 68.9%) as Leicester have come under more pressure, with an inability to keep the ball only inviting more.
Image:Wes Morgan is giving the ball away more this season
MARC ALBRIGHTON - 7.05 DOWN .41 to 6.64
Having been a key player for Leicester last season, starting 34 of 38 appearances, Albrighton's influence - and crossing quality - has waned this time around, despite Leicester breaking their transfer record on a striker renowned for his aerial ability. His accurate crosses are down (1.4 to 1.1), leading to just one assist compared to six in in the previous campaign.
Image:Marc Albrighton's crossing has dropped
SHINJI OKAZAKI - 6.61 DOWN .22 to 6.39
An unsung hero of the previous campaign, Okazaki's tireless running opened space for the likes of Vardy and Mahrez to exploit. However, the Japan international has started just 12 matches this season, following the arrivals of Islam Slimani and Ahmed Musa, with eight substitute appearances contributing to a disappointing rating.
Image:Shinji Okazaki has been marginalised this season
KASPER SCHMEICHEL - 6.78 DOWN .09 to 6.69
In terms of the few players that can claim to have performed to a similar standard this time round, Schmeichel has had to bail his side out at times. The Dane's rating has fallen a little this season due to the increased number of goals being shipped, but not to the extent of any other of last season's regulars. He's been forced into significantly more saves per game (3.5) than the 2015/16 campaign (2.6).
Image:Kasper Schmeichel has been one of Leicester's better performers
ANDY KING - 6.64 UP .08 from 6.56
The only player to have started at least five games this season and last to see his rating increase, in reality little should be read into King's improvement in that regard. Following the sale of Kante, the Leicester stalwart has already played more minutes in 16 appearances this season (1093) than 25 last (1050), with a score of 6.64 this season ranking eighth and hardly worthy of praise.
Image:Andy King is the only Leicester player to improve this season