Rangers snapped Itten up from Swiss side St Gallen following a prolific campaign last term, which saw him bag 20 goals in 36 appearances across all competitions.
It had been thought Rangers would sell Alfredo Morelos in the window, but the Colombian stayed put and Itten has found securing game time tough.
Steven Gerrard started Itten against Falkirk in the Scottish League Cup and McCann, watching on, was quick to notice that the Swiss is not sharp.
He said on BBC Sportsound during the first half after Itten had fired a shot over the goal: “It’s a glaring chance.
“Itten should score or at least hit the target.
“He looks out-of-sorts to me.”
Itten has clocked ten appearances in the Scottish Premiership for Rangers so far this season, scoring twice.
He helped the Gers go in 3-0 up against Falkirk at half time, providing an assist as goals from Jermain Defoe, Calvin Bassey and Borna Barisic put the visitors in command.