Mikel Arteta has revealed Mikel Merino carried on playing after sustaining a suspected shoulder fracture in his first Arsenal training session, with the Spain midfielder expected to be sidelined for “a few weeks”. Merino joined Arsenal this week from Real Sociedad for a fee that could rise to £32.6m and had been in contention to make his debut as a substitute against Brighton on Saturday. But in a major blow to the club’s plans, Merino was injured in 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.” Asked how upset Merino had been after sustaining the injury, he said: “He had the incident and he carried on playing – and training. And at some point we were looking at him and thought he did not look right. That shows you how much he wanted it and he did not want to accept that was happening in that moment. “But actually, that is what happened and now let’s use the time that we have, right now, to make sure he is familiar with everything that we are doing, how we live and what we expect of him, about our team dynamics. He will be in every team meeting as well. We will use the time in the best possible way and in a few weeks he will be ready.” Arteta said he was disappointed to lose Merino but that they must move on quickly. “We fought so hard for three months to get the player over the line. The club made a huge effort to bring him in and on day one for that to happen it’s a huge blow. But his reaction has been exceptional straight away. We signed him for many years, not for a few weeks, and we need to move on. These things can happen, it is very unfortunate but this is our reality.” Gabriel Jesus is not in contention to face Brighton as he continues his recovery from a groin injury. Arteta hopes the academy graduates Myles Lewis-Skelly and Ethan Nwaneri can help provide cover in attacking areas. “We are creating a squad and within that you have to create space for that talent to emerge and have the goal they deserve,” he said. “They are earning that right, certainly. Obviously the gap is so big from where they were playing, to playing in the first team and the demands we have right now. So far they are fulfilling that gap and doing really well.” Arteta paid tribute to Aaron Ramsdale, who has joined Southampton. The goalkeeper will cost £18m up front, with Arsenal set to receive up to £6m in add-ons, including a £1m bonus if Southampton avoid relegation. “He brought a lot of joy and charisma and was really good when he joined,” Arteta said. “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.” Southampton’s manager, Russell Martin, believes Ramsdale has arrived with a target. “He is hungry to become England’s No 1 again and he wants to be here,” he said. “I think that is so important. “If you had asked me four or five weeks ago: ‘Would we have had a chance of signing Aaron Ramsdale?’ I would have thought you were probably crazy but then we’ve spoke a fair bit over that period of time. “Yeah, I’ve pestered him a little bit and even a week ago I would have probably thought it is not achievable, but worth trying still. Then he’s seen the way we’ve played, he’s watched the first couple of games and I think he admires the courage of the players and the way they play. I think he knows he has a chance to express himself and come in and show everyone what a good goalkeeper he is.”