Monchi has already agreed a three-year deal to become Arsenal's new technical director, according to a report.
The 50-year-old left his position as Roma's sporting director on Friday afternoon by mutual consent, a day on from manager Eusebio Di Francesco being sacked.
Having been touted as a target for Arsenal over the past few months, The Sun suggests that Monchi has quickly taken up the Gunners' offer.
Monchi will oversee further backroom changes at the Emirates Stadium, it is claimed, and he joins with the full blessing of boss Unai Emery, who he worked with at Sevilla.
Raul Sanllehi has been tasked with overseeing Arsenal's transfer activity since Sven Mislintat left at the start of last month.
During his time at Sevilla and Roma, Monchi helped to either discover or sign the likes of Dani Alves, Jesus Navas, Sergio Ramos, Jose Antonio Reyes, Cengiz Under, Ante Coric, Justin Kluivert and Nicolo Zaniolo.