
Arsenal boss Arsene Wenger has been left 'surprised and worried' after Theo Walcott suffered an injury setback.
The speedy winger only recently returned to action after a long-term shoulder injury he sustained while on international duty with England.
Walcott made his first start for the Gunners since the problem last weekend and impressed during the 4-0 triumph over Blackburn Rovers.
However, the 20-year-old has damaged his knee during a training session prior to Saturday's trip to Newcastle United and now faces a nervous wait over a scan.
"Walcott got injured today in training," Wenger told the club's official website. "We have to test it, he has a scan on his knee today.
"We are surprised and worried. He was in very good form coming back and that is very bad news for us and for England.
"For the rest of the season might be too long, but he's out of tomorrow's squad and he could be out of the England squad.
"He locked his knee so it could be a cartilage problem. He did it walking back from training. He was fully normal during training but maybe it only came out when he stopped.
"We have to see how he responds today and I hope it's not really serious."

FREAK KO ... Theo Walcott has only just returned from injury
The Arsenal winger’s right knee locked as he left the training pitch yesterday. Gunners boss Arsene Wenger said: “Theo is completely distraught and so am I.
“It could be his cartilage. He felt his knee and it started to swell. It’s very bad news for us. “To say he will be out for the rest of the season would be too long but it is certainly the beginning of May.”
Walcott, 21, has played just four games after returning from a shoulder problem which had ruled him out for nearly four months. He was due to face Newcastle today before linking up with the England Under-21 squad.
Wenger added: “Maybe he did it in training and it came out when he stopped. But we have to see how he responds over the weekend.
“He is really shocked. It is a loss.”
things happen whenever wenger praise his players
Lolx? Haha Walcotts not good at walking
Wad about Ro Sick Y > a man always sick de

Arsene Wenger has told Setanta Sports that Theo Walcott’s knee injury is far less severe than initially feared.
Walcott picked up a freak injury at the end of training on Friday and there were fears that he had suffered cartilage damage.
Such a problem would have ruled him out for five weeks and Wenger said the England star was distraught.
However, a scan has painted a far rosier picture and he should be back in contention in a fortnight.
”The scan was reassuring and it does not look as if there is any damage there,” Wenger told Setanta Sports ahead of Arsenal’s clash with Newcastle.
“It is a swollen knee with some blood in it, but I believe that in 10 or 12 days he should be back.
”You want all your players and it is unfortunate as he was coming back, but the most reassuring thing is there is no serious damage.
”We were scared at one stage that it was a cartilage or ligament, but there is none of that.”
phew..hope he be back for our CL matches...EPL still can cope