An underlying reason for Arsenal midfielder Aaron Ramsey’s recent spate of injuries has yet to be determined, the Gunners’ boss Arsene Wenger told today’s (Friday) press conference at the team’s training grounds in London Colney.

The Welsh midfielder has only recently returned to the pitch after the latest in a string of injuries.

And there has recently been criticism in the press from former Wales football coach Raymond Verheijen calling upon Ramsey to quit Arsenal unless training methods change dramatically.

Wenger told reporters that Ramsey is still out with a “little” hamstring strain.

Asked whether Ramsey had just been unlucky or there was an underlying reason for yet another injury, Wenger replied: “We haven’t found the underlying reason.

“There is an underlying reason that is medical or biomechanical because he is a guy who is serious, works hard, has a controlled and disciplined life, so there is no obvious reason why he should have muscular problems.”

In response to a question about whether his training methods should be changed, Wenger replied that players have “individualised” training and injury prevention regimes – “I don’t think that [anything] has been neglected; we just have to find a reason why it has happened. It is not a major injury, just a Grade one, a small muscular injury.”

Wenger said Arsenal was looking at a couple of weeks more recovery time for Ramsey.

In other team news ahead of Sunday’s FA Cup clash again Middlesbrough, he confirmed that Alexis Sanchez is still out, Jack Wilshere is back in normal training, and Alex Oxlade-Chamberlain is closer to returning – possibly two weeks, or three weeks “maximum”.

Gabriel Paulista is “very close” to making his debut.

Wenger said: “He is a player who likes to defend – it is more and more difficult to find people like that. And a player who has good qualities, he has good pace, is good in the air, and one against one, but I don’t talk too much and let him play, and he shows how good he is.”

Wenger said while he was anticipating a challenge on Sunday, “it is a big opportunity as well – that is how we have to look at it.”

He said it was “lucky” to have drawn to play at the Emirates, and that the game would be treated “exactly like a Premier League game”.

The Gunners’ boss confirmed that Wojciech Szczesny will play, adding, “he is completely ready and impressive in training” and has been responding in a “focused way”.

In regards to Wilshere’s recovery, Wenger said that the Harpenden midfielder has been out for four months and misses competition.

And although he is back to work and very committed it “might take him a while to get back to a competitive level”.

Wenger described Wilshere as motivated and focused to come back as quickly as possible and “is working very hard”.

He went on: “But he has been out for four months and he needs to get back into competition, to get that sharpness training cannot give you, because it is about a combination of fitness and decision-making and the speed of decision-making.

“And it takes a while to get that back.”

One reporter asked about whether he had smiled over England boss Roy Hodgson dismissing the recent controversy over Wilshere possibly smoking a shisha pipe, as he had tried one and - while Arsenal had treated the whole incident very well - the furore in the press was a nonsense as the water pipe had apparently just left him with a fruity taste in his mouth.

Wenger laughed and replied: “Some people must love it because they do it. I have never tried [it] so I can’t tell you anything about that.”

Asked whether the Premier League was worth £5 billion in TV rights, Wenger joked: “I don’t have to decide that, the television has to decide that, but it is an impressive number, and it shows the popularity of the English game.”

He praised the contribution that English football has made to Premier League’s worldwide success.

• Arsenal V Middlesbrough Emirates Stadium, Sunday (15) 4pm