Having just got their exciting young winger fit again, Arsenal could be without him for all or most of the rest of the campaign following a completely different injury...
Arsene Wenger, the Gunners' manager, revealed the news of the injury to his England winger at his pre-match press conference on Friday, but subsequent reports suggest that the problem could be even more serious than the Frenchman had indicated.
It could undermine the plans of both Arsenal and England, and has reportedly left Walcott himself "absolutely distraught" after he battled back from four months out with that earlier shoulder injury,
According to a report in The Guardian, Walcott miss Arsenal's Champions League quarter-final against Villarreal and at least the first leg of any semi-final, as well as the meeting with Chelsea in FA Cup semi-final, and England's qualifier against Ukraine on April 1.
The reports says that Wenger's 'best-case scenario' would mean Walcott being available only for Arsenal's last four Premier League games, and possibly two Champions League matches and an FA Cup final, should the Gunners progress that far in those competition without him.
"He is strong mentally but today I found him really shocked," the paper quotes Wenger as saying. "He is completely distraught. Training was fully normal. Maybe he has done it in training and it came out when he stopped. Walking off the pitch he felt his right knee lock up and it started to swell – it could be a cartilage."
The results of a scan are expected on Saturday, and could spell the end of the season for Walcott, who turned 20 just this week.
Wenger said that Walcott would miss "three weeks minimum – five [before he would be fit] to play".
The manager had recently stated how valuable Walcott's return could be for his team, stressing that he adds an extra dimension to their attacking play.
He said, "We are a bit surprised and worried because he was in very good form coming back.
"He gives us qualities that are different from other players. He's direct, and he goes behind, he has the timing to go behind – he is an interesting quality in the team and when you play from one second to the next you are on the other side of the pitch with him. So it is a loss."
Mark Hinton, Goal.com