By Tony Hughes

Arsenal’s medical staff have hit a brick wall in their attempts to make an exact diagnosis on Alexis Sanchez’s new injury, according to a report.

The Guardian claim there is frustration at the club’s London Colney headquarters over the lack of clarity and their relative lack of power in the situation.

It is said that Arsenal accept that Sanchez has to be considered as a doubt for their Premier League fixture at Manchester United on Saturday week, with one report in The Sun claiming he will be sidelined for six weeks.

It goes on to say that Sanchez will also miss the crunch Champions League matches with Paris Saint-Germain and Basel, along with additional Premier League games against Bournemouth, Southampton, West Ham, Stoke and Everton.

But it is currently impossible for Gunners staff to make an exact diagnosis on the muscular injury that the Chile forward has suffered on international duty.

The Guardian report that the London club’s medical team have been in contact with their Chilean counterparts since Sanchez pulled up with the problem in training before his country’s World Cup qualifier away to Colombia on Thursday.

The Chile football association has described the injury as a “low-grade muscle tear” and has said that Sanchez will not travel to Colombia.

He will remain in Santiago for treatment and assessment, in the hope that he can be fit for Tuesday’s qualifying tie at home to Uruguay.

The potential loss of Sanchez for an extended period of time would be a massive blow for the Gunners, who have made a strong start to the season.

They are unbeaten in all competitions since the opening day defeat against Liverpool, are currently just two points off the pace in the Premier League and have already qualified for the last 16 of the Champions League.

Sanchez has been a big part of this and has made 15 appearances in all competitions, scoring eight goals and supplying seven assists.

Arsene Wenger has decided to use the Chilean international to spearhead Arsenal’s attack this season and he is currently keeping Olivier Giroud out of the starting XI.

A long-term injury could see the French international get his chance to reclaim his spot as the no.1 striker for the Gunners.

In other Arsenal team news, Hector Bellerin has given the club a boost by signing a new six-year deal worth over £31.2million.