The Daily Mail reports that Merino is set to miss up to two months after fracturing his shoulder in his first training session with the club. Mikel Arteta confirmed that the big-money signing from Real Sociedad had been injured in an inadvertent clash with Gabriel in training, and he is now set for a prolonged absence.

Merino was Arsenal's marquee midfield signing but the 28-year-old could be out for a significant period. The earliest date of a potential return appears to be the middle of October, but there is also the prospect of a lay-off until early November. The Gunners are hopeful he could return after next month's international break, potentially in a clash with Bournemouth on October 20.

Merino is a Spain international with 28 caps, and was a remarkably consistent player for Sociedad. During his time at the club, he made a total of 242 appearances.

Arteta will have some decisions to make when Arsenal take on Spurs after the international break. Declan Rice is suspended, while Merino is also unavailable.