Runarsson was signed as a third-choice keeper before Emiliano Martinez left for Aston Villa, and the Icelandic international so far hasn’t proved to be the able deputy Arteta needs.
Arsenal had a £10m bid for Raya rejected last summer, so would probably have to go to around £15m to land the highly-rated 25-year-old – but it is doubtful whether promotion-chasing Brentford would sell.
A more feasible short-term option could be Brighton keeper Mat Ryan.
The Australia international has fallen out of favour in recent weeks, and could be available for half the likely price of Raya.
He would provide able back-up for Bernd Leno, giving Arteta and Edu a chance to put a bid together for Raya in the summer.