Mikel Arteta has said Arsenal’s new signing Mikel Merino is set to be sidelined for “a few weeks” after sustaining a suspected shoulder fracture in his first training session.

The Spain midfielder, who joined last week from Real Sociedad for a fee that could rise to £32.6m, was in contention to be a part of the squad for their Premier League game against Brighton on Saturday. But Arteta revealed Merino had been injured after a collision with the defender Gabriel Magalhães on Thursday.

“It looks like he’s going to be out for a few weeks,” said the Arsenal manager. “He was really excited and everything was looking really good. He landed on the floor and Gabi landed on top of him and it looks like he has a small fracture probably. We have to see [how long he is out]. He was in so much pain. We’ll have to do some more tests on that and then we’ll have more conclusive answers.”

Arteta also said Gabriel Jesus was not in contention as he continues his recovery from a groin injury. The Bournemouth goalkeeper Neto is expected to complete a loan move to replace Aaron Ramsdale, who has joined Southampton.

“He brought a lot of joy and charisma and was really good when he joined,” Arteta said of Ramsdale. “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.”