Gazzetta dello Sport reporter Nicolo Schira has revealed the Gunners are discussing a £31million deal.
Manolas, 27, is available for £31.1m (€36m) due to a release clause in his contract.
And Arsenal are in talks with the Greece international's agent Raiola, who was given a three-month ban by the Italian Football Federation (FIGC) last week, which was extended worldwide by FIFA's disciplinary committee.
“Arsenal are really interested in signing Kostas Manolas, who is expected to cost €36M (termination clause) from Roma," Schira wrote on Twitter. “Contacts ongoing between Gunners and his agent Mino Raiola."