Arsenal midfielder Alex Oxlade-Chamberlain faces around three weeks out with a hamstring strain suffered against Manchester United.
According to the Daily Telegraph, the England international is waiting on the results of a scan but Arsenal believe he could miss between three and four weeks.
The Gunners star pulled up in the second half of Arsenal's 2-1 win at Old Trafford in the FA Cup on Monday night.
And if the initial prognosis is correct, Chamberlain looks set to miss the crucial Champions League tie against Monaco in France next week as well as England's Euro 2016 qualifier against Lithuania and friendly against Italy.
Chamberlain was excellent for Arsenal before injury struck, setting up Nacho Monreal's opener with a weaving run through the United back line. Danny Welbeck scored the winner against his old team to set up a semi-final match against Bradford or Reading.
Chamberlain had just hit a bit of form after struggling to cement a starting spot this season, so this injury will come as a big blow to the youngster. He will also be a doubt for Arsenal's crunch fixture against Liverpool on April 4.
It's also bad news for Roy Hodgson, who would have had Chamberlain pencilled into his squad for the two upcoming internationals.
On a more positive note for Arsene Wenger, the Arsenal boss has plenty of options to replace Chamberlain. Although he's gifted and an important player to Arsenal's attacking fluidity, the Gunners are well stocked in attacking midfield.
In the short term, expect to see the likes of Danny Welbeck fill in on the flanks, while Wenger can also call on Santi Cazorla, Theo Walcott and Tomas Rosicky.
Arsenal fans will just be praying Wenger has a fully fit squad to choose from when the Premier League run-in reaches its climax, with that fixture against Liverpool looking like an increasingly vital match.