David Moyes' chances of claiming a Champions League quarter-final berth in his first season as manager of Manchester United have been given a boost after Javier Saviola was ruled out of Tuesday evening's round of 16 tie.
The Olympiakos striker picked up a thigh injury over the weekend, and Sky Sports News confirmed that the Argentinian won't be fit to feature against the Red Devils:
That being said, the Greek hopefuls aren't the only outfit with injury concerns for the remainder of their round of 16 examinations. Read on for a breakdown of the key injuries currently testing each club left in this season's Champions League.
For each team's injury concerns, according to UEFA.com, click on the relevant team name below:
Next Fixture: Bayern Munich (A), March 11
It could be just too much of an ask to expect Aaron Ramsey to recover from his thigh injury in time for the trip to the Allianz Arena next month, while Kim Kallstrom is likely to also be going through the last phases of his recovery from a back issue.
Theo Walcott will, of course, still be missing through his serious knee injury, while Kieran Gibbs is also a doubt at left-back, but Arsene Wenger can hope to see Thomas Vermaelen back on his bench, putting a calf strain behind him.
Lukasz Fabianski will continue to deputise in goal for the North Londoners after Wojciech Szczesny was sent off for a foul on Arjen Robben in the first leg.
Next Fixture: Milan (H), March 11
With a 1-0 aggregate lead to their name heading back to Madrid, Atletico currently have just a couple of injury concerns.
Javi Manquillo will miss the return leg against the Rossoneri thanks to a serious neck injury, but Tiago is hoping to make a return for the March fixture despite knocks to his wrist and knee.
Next Fixture: Manchester City (H), March 12
Gerardo Martino's side are fortunate in boasting close to a clean bill of health, with Gerard Pique the only major fitness headache. The centre-back looks set to miss the return leg against Manchester City, but Barca have a two-goal lead to defend.
Jonathan Dos Santos, who isn't a first-team regular anyway, is the other injury doubt.
Next Fixture: Paris Saint-Germain (A), March 12
Rupturing the anterior cruciate ligament in his right knee has meant that Robbie Kruse will miss the remainder of the season, but Sami Hyypia will be pleased to report that it's not all that severe in his squad.
Eren Derdiyok and Stefan Reinartz have issues with their thigh and foot, respectively, but they can be hopeful of making their returns in time to try to salvage the 4-0 deficit they slipped to against Paris Saint-Germain.
Next Fixture: Arsenal (H), March 11
Not only does Pep Guardiola boast one of the strongest squads in the world, but it's also a close to fully fit one, too.
That being said, the ongoing absence of Franck Ribery could affect the squad, with Xherdan Shaqiri also missing from the wide areas, although both are hoping to be back for their home leg.
Bastian Schweinsteiger missed the first leg against Arsenal, but he has begun to get some playing time in the Bundesliga, making a couple of appearances after a lengthy absence.
Next Fixture: Zenit St. Petersburg (A), Feb. 25
This will be Dortmund's first European trial of the season since losing Jakub Blaszczykowski to an anterior cruciate ligament injury in late January that's set to keep him sidelined for the remainder of the campaign.
Also on the long-term list still sits Neven Subotic, but the official Borussia Dortmund Twitter account posted that both Robert Lewandowski and Mats Hummels were in line to feature against Zenit St. Petersburg this week:
Sven Bender has been ruled out of the trip to Russia with an inflammation of the groin, while Ilkay Gundogan could also miss out due to a hip injury.
Next Fixture: Galatasaray (A), Feb. 26
Ahead of a crucial matchup in Istanbul, John Terry is the only relatively new doubt listed by UEFA as a doubt for Chelsea, but he is expected to feature after his late winner against Everton.
Marco van Ginkel continues his recovery on the sidelines, while Nemanja Matic is cup-tied.
Next Fixture: Chelsea (H), Feb. 26
Aydin Yilmaz is out of the Wednesday evening visit of Chelsea, but Roberto Mancini also has a number of late fitness tests to assess this week.
Aurelien Chedjou, Hamit Altintop, Gokhan Zan and Hakan Balta are each listed as doubts for the Istanbul hosts.
Next Fixture: Barcelona (A), March 12
Martin Demichelis will miss out on next month's visit to Catalan country through suspension, while Sergio Aguero, Fernandinho and Matija Nastasic continue to contend against absences, although all can hope to be fit for the second leg against Barca.
Next Fixture: Olympiakos (A), Feb. 25
Defence is the main area of concern for David Moyes, who is currently waiting to see if Jonny Evans, Phil Jones, Rafael and Rio Ferdinand will be fit the midweek affair against Olympiakos.
Marouane Fellaini is back, but Nani provides cause for concern with hamstring complications, while Danny Welbeck's knee reportedly makes him a slight doubt.
Next Fixture: Atletico Madrid (A), March 11
Clarence Seedorf faces a squad conundrum for Milan's trip to Atletico Madrid next month, with a number of key players set to miss out.
Riccardo Montolivo will miss the match through suspension, while Valter Birsa and Stephan El Shaarawy remain among the longer-term absences.
Kaka and Cristian Zapata are both racing for fitness to make it back in time for the Spanish fixture, while Robinho and Bryan Cristante are more serious concerns with thigh and leg problems, respectively.
Next Fixture: Manchester United (H), Feb. 25
After selling Kostas Mitroglou to Fulham in the January transfer window, attacking absences are the last thing Olympiakos need. But Nelson Valdez joins Javier Saviola on the injury table, although there's a small chance the Paraguayan could recover from his ankle knock in time to face Manchester United.
Jose Holebas could miss out with a knee knock after featuring in five of his side's six group fixtures.
Next Fixture: Bayer Leverkusen (H), March 12
Edinson Cavani missed the first leg in Leverkusen, but Paris Saint-Germain manager Laurent Blanc will feel hopeful of seeing the Uruguayan back in his squad for the visit of the Factory Squad in a fortnight's time.
Zoumana Camara and Christophe Jallet aren't as much worrying absences for the team, but PSG can hope that both will be back in time to provide cover if needed.
Next Fixture: Schalke (A), Feb. 26
For Carlo Ancelotti, an almost fully fit squad means that Sami Khedira, still making his return from an ACL tear, is the only player set to miss out on this week's fixture at the Veltins-Arena.
Next Fixture: Real Madrid (H), Feb. 26
Schalke are the most injury-plagued outfit left in the round of 16, with no less than seven players down as doubts for this week's visit of Real Madrid.
Among the most impacting injuries is Benedikt Howedes and Atsuto Uchida in defence, while the concerns around Julian Draxler, Dennis Aogo and Marco Hoger will worry Jens Keller in regards to his midfield options.
Next Fixture: Borussia Dortmund (H), Feb. 25
Compared to round of 16 opponents Borussia Dortmund, Zenit are far better off in terms of injury, but while their figure is far fewer, the importance of each potential absence is big.
Per Jonathan Walsh of TNC Bundesliga, the Russian hosts have equal injury concern in defence, midfield and attack with Cristian Ansaldi, Roman Shirokov and Danny all set to miss out on the first leg against the Black and Yellows: