Arsenal manager Mikel Arteta has said that new signing Mikel Merino will be out of action for 'a few weeks' after suffering a shoulder injury during his first training session with the club.

Merino, a £33million arrival from Real Sociedad in Spain, had been hoping to make his Gunners debut against Brighton on Saturday.

However, he will now have to wait until late September or early October following an accidental training ground clash with Arsenal defender Gabriel. 

'Yes, very unfortunate,' Arteta told reporters on Friday. 'Yesterday he had a collision and he has got a shoulder injury unfortunately. It looks like he is going to be out for a few weeks.

'First session with us. It was looking exciting, we were all very excited, everything was looking very good… he landed on the floor and Gabi went on top of him.

Midfielder Mikel Merino joined Arsenal earlier this week in a £33m move from Real Sociedad

'It looks like he has got a small fracture probably.

'We will have to see [how long he will be out]. He was in so much pain. We have to wait to do some more tests, then we will have more conclusive answers. This is football.' 

Merino's injury is a big blow for Arsenal, who are still without Brazilian striker Gabriel Jesus, Scottish left back Kieran Tierney and Japan defender Takehiro Tomiyasu.

Arteta also spoke about Aaron Ramsdale during Friday's press conference.

Goalkeeper Ramsdale has left the Emirates to join Southampton and Arteta said: 'Thank you so much for what he's done for the club, for the team and for myself.

'He brought a lot of joy and charisma and was really good when he joined.

'He had a situation that was really good for him. He insisted that he's really joyful when he plays and we tried to arrange that.'