Torreira, 22, joined in a £26.5million deal from Sampdoria in the summer and he has been one of the signings of the season.
But the Uruguayan’s all-action displays in the centre of midfield haven’t impressed pundit Cascarino, who has hit out at him for lacking position sense to play the role.
“Unai Emery needs a long-term plan for how to tighten up his Arsenal team at the back,” Cascarino told The Times following the 3-1 FA Cup defeat to Manchester United.
“They get caught with real sucker-punch goals. His full backs play in advanced positions but when they are out of position upfield and the ball is lost, there is no top-class holding midfielder to plug the gaps.
“Lucas Torreira is a fine player, a tenacious tackler who can join the attack effectively, but he does not have the positional sense needed by a midfield anchor.
“He is unable to work out where best to intercept dangerous passes, as was shown when Romelu Lukaku picked out Alexis Sanchez for United’s first goal.”
While Paul Merson wants Arsenal to sign Watford star Abdoulaye Doucoure who is “much better”.
Merson told Sky Sports: “Everyone was raving about Lucas Torreira, but he’s not that good. 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.”