Only weeks after recovering from a hamstring injury which ruled him out in January and February, Leicester's Jamie Vardy has been sidelined by a knee issue.
Vardy picked up the problem in the 1-0 Premier League win over Leeds and his absence will be a huge blow for the Foxes who have fared far better with the striker than without him this campaign.
However, Vardy is not the only key player to have been missed by their side this season. Planet Sport picks out six players their teams just can't do without - including a surprise name at Liverpool.
Thiago Alcantara (Liverpool)
Amid a sea of Manchester City stars at the top of the Premier League's points per game charts is a sole Liverpool player.
Thiago has missed 12 Reds games this season through a combination of hip, calf and thigh injuries and a bout of Covid-19. Jurgen Klopp's side have only lost one of those games but five draws have seen their points per game dip to 1.92. Not too shabby but top-four rather than title-winning form.
With the 30-year-old in their ranks, Liverpool have won 13 and drawn one of their 15 games.
That gives Thiago a points per game average of 2.67, the highest in the division ahead of Ilkay Gundogan (2.6).
And it's clear to see what the Spain international brings to the Liverpool team when you delve further into the stats.
While their goal output is pretty similar with or without him in the side (2.66 with, 2.58 without), their defensive record is far superior when he plays. In the 12 games he has missed they have conceded 13 times, while in the 15 games he has played they have let in just seven.
PPG with Thiago: 2.67
PPG without Thiago: 1.92
Angelo Ogbonna (West Ham)
West Ham were second in the Premier League, level on points with Manchester City and had just beaten Liverpool 3-2 when it was confirmed Ogbonna had ruptured his anterior cruciate ligament.
The Irons had won seven and drawn two of the games the defender had been involved in, picking up an average of 2.1 points across the 11 games.
Since then, despite still being on the periphery of the Champions League chase, David Moyes' side have lost seven of their 17 top-flight games. Six wins and four draws have come in Ogbonna's absence but an average points per game return of 1.3 is some way from top-four form.
Despite the 33-year-old being in the latter stages of his career his experience and cool head are what binds West Ham's defence together. The Italian has been a huge miss this season.
PPG with Ogbonna: 2.1
PPG without Ogbonna: 1.3
Jamie Vardy (Leicester)
Of the seven games Vardy has missed this season, the Foxes have picked up just five points, winning just one of them for an average of 0.71 points per game.
With the former England striker in the side, they are averaging 1.56 points, having won eight and drawn four of 18.
Vardy has scored ten during that sequence but surprisingly it is not goals Leicester are missing in his absence - they actually average more goals per game without Vardy, 1.86 as opposed to 1.5. The Foxes are, in fact, much more open when shorn of Vardy, letting in 2.29 goals per game compared to 1.5 with him.
PPG with Vardy: 1.56
PPG without Vardy: 0.71
Ismaila Sarr (Watford)
Watford are struggling but what is patently clear is that they would be down and out without Sarr's contributions to the cause, including his five goals.
The Hornets' 4-1 thrashing of Manchester United in November was marred by an injury to Sarr who was subsequently ruled out with ligament damage. Then Africa Cup of Nations duty resulted in him not making his return until February 12.
Watford were 16th, four points clear of the relegation zone following the humbling of United, but then went on to pick up just two points from 30 with Sarr sidelined.
A win and an assist against Aston Villa marked his first full game back, while he also featured in the draw in the reverse fixture with Manchester United before a muscle strain ruled him out of the defeats to Arsenal and Wolves.
If Watford are to survive, they will be hoping it isn't another long-term absence doesn't scupper their plans.
PPG with Sarr: 1.06
PPG without Sarr: 0.17
Kalvin Phillips (Leeds)
Let's be honest, Leeds haven't been doing particularly well with Kalvin Phillips in the side. With the England midfielder in their ranks they have picked up just 15 points from 12 games, winning three and drawing six.
However, robbed of his services, most recently because of a long-term hamstring injury, they are a full-blown disaster zone.
It's not just the defeats - 12 in 16 games - but the manner of them. Forty-nine goals have been shipped in those 16 games, with 30 coming in just six fixtures thanks in part to 5-1, 6-0 and 7-0 maulings.
Phillips is back in training and expected to return to the side in mid-March. His return cannot come soon enough for new boss Jesse Marsch.
PPG with Phillips: 1.25
PPG Without Phillips: 0.5
Aaron Ramsdale (Arsenal)
Signed in late August from Sheffield United, Ramsdale had already missed the Gunners' opening-day defeat to Brentford before witnessing the subsequent losses to Chelsea and Manchester City from the bench.
Handed his debut against Norwich, he proceeded to keep a clean sheet and has been an ever-present since as the Gunners have stormed into a Champions League spot.
The contrast between no goals and no points from three games with Arsenal's subsequent form cannot be attributed solely to Ramsdale. However, his contribution cannot be under-estimated. Maybe shelling out £30million for a relegated keeper wasn't such a bad move after all.
PPG with Ramsdale: 2.18
PPG without Ramsdale: 0