Mikel Arteta is sweating over the fitness of key defender David Luiz after the Brazilian sustained a neck injury.
According to The Athletic, Luiz's issue requires particular caution and he could face an extended period out on the sidelines.
As a result, Rob Holding is expected to remain at Arsenal rather than join Newcastle on a loan deal.
Luiz is expected to miss Arsenal's Premier League opener against Fulham on Saturday in the early kick-off at Craven Cottage.
If the Brazilian Luiz, 33, is set for a prolonged absence it would be a major blow for Gunners boss Arteta ahead of his first full season at the Emirates.
Shkodran Mustafi, Calum Chambers and Pablo Mari are all returning to fitness after their own injury issues while new arrivals William Saliba and Gabriel are untested in the Premier League.
Sokratis Papastathopoulos has been unfancied by Arteta ever since he arrived as manager but the Spaniard might be forced to turn to him in the coming weeks.