The Switzerland midfielder completed a £35million move from Borussia Monchengladbach to Arsenal last summer but has failed to live up to expectations.
Xhaka’s has received more red cards (2) than he has scored goals (1) in the league this term.
His performances haven’t been up to scratch with his latest disappointing display coming in Arsenal’s 3-0 defeat to Crystal Palace on Monday night.
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And asked for this thoughts on Xhaka’s debut campaign in the Premier League, Cascarino didn’t hold back.
“Arsenal spent over £90million in the summer and none of the signings have proven themselves,” he told talkSPORT.
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Alexandre Lacazette (Lyon)
“Lucas Perez has hardly had a kick, he’s in and out of the team. He looks a good player but just doesn’t play often enough.
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“Granit Xhaka has been one of the worst signings of the season. Maybe the worst of all time?
“He’s been very poor.”