Real Madrid’s preparations for their blockbuster Champions League showdown against Manchester City have been thrown into further disarray. While the club were already reeling from the confirmed absences of Jude Bellingham and Kylian Mbappe, a fresh injury concern surrounding left-back Alvaro Carreras has left manager Alvaro Arbeloa facing a defensive headache. The Spaniard is now a major doubt for the first leg after picking up a heavy blow to his left calf during domestic action.Although there is some slight optimism within the medical department, his availability for the upcoming European clash is far from guaranteed, ASreports. The defender spent Saturday working in the gym and undergoing intensive physiotherapy rather than training on the grass, leaving his fitness status to be evaluated on a day-to-day basis as the match against Manchester City approaches. The round-of-16 first leg is scheduled to take place this coming Wednesday, leaving the Spaniard with very little time to prove his fitness.The situation regarding the club’s marquee stars is clearer but frustrating, as both Jude Bellingham and Kylian Mbappe are certain absentees for the first leg. Bellingham continues his recovery from a severe muscle tear sustained in February, while Mbappe’s left knee is showing signs of improvement. The focus for both superstars is now firmly on the return leg at the Etihad Stadium, with the club hopeful they can play a part in the deciding fixture of the tie. Eduardo Camavinga has provided a rare boost for Arbeloa after returning to full training following a persistent tooth infection. Despite some discomfort, the Frenchman is expected to be available for selection, a welcome development after a turbulent period where he was excluded against Getafe and left in the stands during Madrid's 2-1 win against Celta Vigo on Friday. Although he travelled to Vigo, many believe Arbeloa’s pointed comment: “I’m very happy for the people who wanted to come,” was aimed directly at the midfielder’s recent situation.Add GOAL.com as a preferred source on Google to see more of our reportingReal Madrid’s squad is looking increasingly thin, with only 17 first-team players currently available. Long-term absentees Eder Militao and David Alaba remain out, while Rodrygo prepares for ACL surgery. Arbeloa must now find a way to navigate the first leg without several influential figures.