Arsenal completed four first-team signings in the summer transfer window, but questions remain over whether there is enough depth in the squad. The Gunners recruited goalkeeper Neto, defender Riccardo Calafiori, midfielder Mikel Merino and attacker Raheem Sterling, but have already suffered a crisis in midfield. Merino suffered a nightmare as he picked up a long-term injury in his first training session, and with Martin Odegaard picking up an ankle problem during International duty, Arsenal are suddenly short of midfield options. This has raised the question over whether there is enough depth …