Arsenal’s new €32.5 million ($36m) signing Mikel Merino will be out for several weeks after suffering a fractured shoulder in his first training session, manager Mikel Arteta confirmed on Friday.

The 28-year-old midfielder sustained the injury when colliding with centre-back Gabriel Magalhães during practice at London Colney.

Merino, who joined Arsenal from Real Sociedad, was hopeful of making his debut against Brighton in Saturday’s Premier League clash at Emirates Stadium but is now set for a spell on the sidelines.

“Very unfortunate,” Arteta told a news conference. “Yesterday [Thursday] he had a collision and he has a shoulder injury unfortunately. It looks like he’s going to be out for a few weeks. First session. 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 for]. He was in so much pain. We’ll have to do some more tests on that and then we’ll have more conclusive answers.”

There was better news regarding forward Gabriel Jesus, who underwent an MRI scan on a groin injury amid fears he could be ruled out for a lengthy period.

However, while Arteta ruled out the Brazil international against Brighton, he added: “He is progressing really well. He had a little muscle injury and he is doing quite a lot of stuff already, so we expect him to be with us pretty soon.”

Meanwhile, Arteta insisted Arsenal are open to late moves in the market but refused to be drawn on speculation linking the club with Raheem Sterling.

Sources have told ESPN that Sterling has been offered to Arsenal but when asked if that was the case, Arteta said: “I’m not gonna be talking about this kind of thing sorry.”

Speaking more generally about the window, Arteta said: “Overall, we have tried to do all the things that we wanted. There was a lot to do. There’s still a few hours to go. We are prepared.

“Let’s see. It’s always possible. In the last hours of the transfer window never rule anything out.”

Arteta confirmed Arsenal would ideally like to replace both Aaron Ramsdale and Karl Hein before tonight’s deadline.

Ramsdale completed his £25m ($32.9m) move to Southampton this afternoon while Hein left to join Real Valladolid on loan.

ESPN reported on Friday that Arsenal are open to signing two goalkeepers with a move for Bournemouth’s Neto at an advanced stage, and Arteta said: “It’s clear that we have lost Karl and Aaron so we have to replace them both.

“First of all just say thank you so much for what he’s done for the club, for the team and for myself.

“When he joined he brought a lot of joy and charisma and energy and he was really good at that time. But then things developed. He had a situation where he was insisting a lot that he was happiest when he plays.

“We have tried to fulfil that desire that he had. He looked really excited and happy the other day. He’s joining a great club and a great coach, he looks really excited so I think we are all happy for him.”