According to BBC Sport, Eberechi Eze is facing up to six weeks on the sidelines after suffering a calf injury in last week’s win over Bayer Leverkusen.
The midfielder initially played down the issue but missed the Carabao Cup final defeat to Manchester City. After the game, it was confirmed he would withdraw from England duty and Mikel Arteta said the club would have a clearer picture once scans were completed later in the week.
If the initial prognosis holds, Eze is likely to miss most, if not all, of April. That could mean up to seven games, including quarter-final ties with Southampton and Sporting Lisbon, and potential semi-finals should Arsenal progress.
There are also key league fixtures on the horizon, including a trip to Bournemouth and a crunch meeting with Manchester City that could have a major bearing on the title race.
The timing is far from ideal. Eze had begun to find his rhythm in the number 10 role, and his absence leaves Arteta short of options in a critical area. Martin Odegaard is working his way back from a knee problem, but his stop-start season makes it difficult to rely on his availability.
Arsenal are also without Mikel Merino, who is expected to miss the remainder of the campaign, while Ethan Nwaneri, who provided cover earlier in the season, is currently out on loan at Marseille. It remains to be seen whether there is any appetite to bring him back. Previous reports have suggested there is no break clause in the deal that took him to the Stade Velodrome.
In the meantime, Arteta may have to get creative. Kai Havertz could drop into midfield, Bukayo Saka might be used centrally, or 16-year-old Max Dowman could be handed more responsibility as the run-in gathers pace.