Premier League managers are already feeling the strain amid cascading numbers of COVID-19 cases and mid-season injuries. Now many top bosses stand to lose stars to the Africa Cup of Nations.
Africa's greatest football show – now commonly known as AFCON – gets under way on Sunday in Cameroon.
Although the 2019 edition was held in June and July, it has historically been a January-into-February tournament and has returned to that place on the calendar.
A host of Premier League big names are hoping to make an impact during the four-week tournament, which falls slap-bang in the middle of European club campaigns, causing a major clash of competitions.
Premier League clubs certainly cannot complain of a lack of fair warning. It was June 2020 when African football chiefs decided the 2021 edition of the tournament would have to be pushed back by 12 months to a January 2022 start, in the hope the coronavirus crisis would have eased.
Here, Stats Perform takes a look at which teams from the English top flight might feel its impact the most.
Can Reds cling on in title battle?
If Liverpool lose no further ground on leaders Manchester City by the time their stars return from AFCON, then Jurgen Klopp would surely settle for that.
The 2019-20 Premier League champions have taken two points from a possible nine to leave the title as effectively City's to lose, and now Klopp is going to have to get by without Mohamed Salah, Sadio Mane and Naby Keita.
Egyptian striker Salah is the Premier League's leader in goals (16) and assists (9, level with Trent Alexander Arnold) so far this season. He has taken 80 shots in 20 games (38 of these have hit the target), played 12 throughballs and created 40 chances from open play: in each of those categories he is at the top of the Premier League charts for players defined by Opta as forwards.
How do you cope without such a contribution? Having Mane on hand would help, but Mane will be turning out for Senegal, a team who, like Salah's Egypt, are firmly in the mix as serious trophy contenders. Don't expect either back at the end of the group stage.
Mane has eight Premier League goals this term, including the opener at Chelsea recently. That goal return puts Mane joint-second among African scorers in the Premier League this season, level with Watford's Emmanuel Dennis, who is not in Nigeria's squad.
Mane has played 19 throughballs and has made 23 tackles to boot, which is the seventh highest number of tackles by a forward in the league this season, a rarely mentioned attribute of his game. He does not always tackle with his elbow, either.
Keita will presumably be less of a miss, with the Guinean's Anfield contribution remaining underwhelming, but Liverpool have been so hard hit by absentees recently that to lose anybody for up to five weeks is an inconvenience.
They are at least assured of Joel Matip's presence this month. The centre-back last played for Cameroon in 2015 and has retired from international duty. That is bad news for the AFCON hosts but helps Liverpool, given Matip remains a sturdy presence, with a duel success of 69.47 per cent this season ranking him third among Premier League defenders with 10 or more appearances, and a passing accuracy of 88.89 per cent putting him eighth in that metric.
Liverpool only have two league games inked in between now and the end of AFCON, against Brentford and Crystal Palace, but the Reds also have two postponed fixtures to be slipped in somewhere along the line.
Pep Guardiola's Manchester City hold a 10-point lead over second-placed Chelsea, with Liverpool a point further back but possessing a game in hand on the top two. Reigning champions City have won 11 straight Premier League games and the Citizens have the resources to be able to cope with the short-term loss of Riyad Mahrez, who will captain Algeria.
Mahrez's six goals and four assists this season have come at a startling rate. Given the depth in City's squad, he does not always start, so to appreciate his contribution it is worth looking at his numbers per 90 minutes on the pitch.
The former Leicester City forward is averaging 0.64 goals and 0.43 assists per 90 minutes – impressively close to Salah's return of 0.81 and 0.45 in those categories – and is one of only four Premier League players with 10 or more appearances to average at least 1.00 goal involvements per 90 (Michael Olise 1.43, Salah 1.26, Roberto Firmino 1.24, Mahrez 1.07).
The Blues of Chelsea may have concerns over the absence of goalkeeper Edouard Mendy, given the Senegalese's stabilising influence at the back. His save percentage of 77.14 has only been beaten this season in the league by Wolves' Jose Sa (80.82) and Arsenal's Aaron Ramsdale (77.46).
Spaniard Kepa Arrizabalaga struggled in the early stages of his Chelsea career and is now the undoubted understudy.
Yet Kepa's form when given an opportunity this season has not given such cause for concern. The former Athletic Bilbao goalkeeper has been chiefly used in cup action, and he has achieved a remarkable save percentage of 81.48, suggesting that for a short run of games, he could be a perfectly able deputy.
Can an exodus to Africa affect the race for Europe?
Will fourth-placed Arsenal miss Pierre-Emerick Aubameyang? It seems unlikely now, given he was dropped and stripped of the captaincy after a disciplinary breach before heading off to join Gabon. He has not played for a month. The Gunners won five games in a row without him, including four in the league, before being unlucky to lose to Manchester City.
Cold facts tell us Arsenal have a points average of 1.9 per Premier League game when Aubameyang has started games this season, and 1.5 when he has been either a substitute or out of the team, but those figures may not be significant given the momentum Mikel Arteta's players have built in the recent absence of the 32-year-old. His continuing exile from the first team seems unlikely to cause much consternation.
For manager Arteta to lose Thomas Partey (Ghana) at this point is a blow though, with the former Atletico Madrid player having been excellent in the 2-1 defeat to City, having been slowly building up to such a performance. He had more touches, won more duels, made more tackles and played more successful passes than any other Arsenal player.
Arsenal have a big derby at Tottenham coming up on January 16, and they might feel Partey's absence that day, particularly given Spurs, who currently sit sixth, are sending no current first-teamers away to AFCON.
Splitting the north London rivals for now are West Ham, in fifth, and it will surely have hurt David Moyes to wave off Said Benrahma for a month of Algeria duty. The playmaker has five goals and four assists in the league this season, as well as making 83 ball recoveries and creating 21 chances in open play. That makes him one of only 13 players in the competition to top both 80 recoveries and 20 open-play chances created, and one of only five Premier League stars to tick both boxes and score at least five times. Crystal Palace's Wilfried Zaha, away with Ivory Coast, is another member of that small group.
Seventh-placed Manchester United will lose Eric Bailly to Ivory Coast too. But with Phil Jones back in the first team, will Bailly be missed? The former Villarreal centre-back has played just 217 minutes in the Premier League this season. United youth prospect Hannibal Mejbri is also away, in his case with Tunisia.
Further into mid-table, Wolves must find an alternative to the excellent Romain Saiss (tackle success rate 72.73 per cent) on the left side of their defence, after he joined up with Morocco. Brighton and Hove Albion powerhouse Yves Bissouma has the highest tackle success rate among midfielders to have made more than 40 such challenges in the Premier League this season (50 attempted, 35 won: 70 per cent hit rate) and he will line up for Mali after ending an international exile.
Leicester City sent away striker Kelechi Iheanacho (2 goals, 4 assists this season) for Nigeria service at a bad time for the Foxes, given injured Jamie Vardy faces several weeks out of action.
Palace are firmly in favour of players heading away to represent their countries, but the Eagles never particularly like to be without Zaha (5 goals, 1 assist, 86 dribbles). Since his return from Manchester United in August 2014, Palace have averaged 1.2 points and a 32.9 per cent win percentage with Zaha in their starting line-up, and 0.9 points and a 24.5 win percentage when he has not been in that matchday XI. The loss of Cheikhou Kouyate (80.56 per cent success rate from 36 tackles) to Senegal duty may also diminish the sturdiness of Patrick Vieira's Eagles spine.
Can Clarets cope without Cornet?
The relegation scrap seems more likely to be affected by transfer market activity than departures to AFCON.
Newcastle United and Norwich City, the league's bottom two, are sending nobody away, while fourth-bottom Watford have kept Dennis (8 goals, 5 assists) and it remains to be seen what happens to Ismaila Sarr (5 goals), who has been absent with injury of late but has headed for checks with Senegal doctors.
Burnley, who sit 18th, are seemingly the team to watch carefully here. Maxwel Cornet, now away with Ivory Coast, has scored six Premier League goals from just 10 shots on target, and Sean Dyche must find a way to make the Clarets impactful without the former Lyon man.