The defender has been linked with a move to the Premier League, with the Gunners and Chelsea interested in the 28-year-old.
But Football Insider claim Arsenal are in pole position to land Manolas.
Chelsea are said to be focusing their attention on Manolas' team-mate Radja Nainggolan instead.
The Belgium international is a priority target for incoming Blues boss Antonio Conte.
Gunners manager Arsene Wenger reportedly offered £8m for Manolas two years ago but the move fell through at the eleventh hour.
And the Frenchman has reignited his interest in the Greece international, who joined Roma for £10m in 2014.
Wenger has highlighted the centre-back position as one of his priorities this summer as he looks to lead Arsenal to their first Premier League title since 2004.
