Uruguay international Torreira was signed from Sampdoria for £26 million in July 2018, but Merson has been left unimpressed by the impact he has made at the Emirates.
The Sky pundit, who played for the Gunners from 1985-1997, has identified Doucoure as the ideal man to take the 22-year-old's place in Unai Emery’s midfield.
“Everyone was raving about Lucas Torreira, but he's not that good,” he told Sky Sports.
“I said this a few months ago and everyone kicked up a stink. He only looks good as he's what Arsenal have needed for a long time, someone to run around and put their foot in.
“But if you put him up for sale tomorrow, then none of the top five clubs in the Premier League would be interested.
"They should sign Abdoulaye Doucoure at Watford - he'd walk into the team. I'd take him tomorrow morning. He's a much better player than Torreira and he scores goals. He's one of the most under-rated players in the Premier League - he could play for any of the top six.
"It seems no one pays attention to him because he plays for Watford and fans will say, 'Why are we buying him, he's at Watford?' - but he's a proper player.”
Doucoure has been vocal about his desire to leave Vicarage Road for a Champions League club, and PSG have been hotly linked with the 26-year-old who 'no one' is paying attention to. No one.
