The former Rangers man believes players like Joe Garner and Michael O'Halloran are struggling.
Rangers have endured a difficult return to life back in the Scottish Premiership after securing promotion last season.
They are currently second in the table behind Celtic, who are eight points clear at the top and have two games in hand over their rivals.
There has been plenty of criticism of manager Warburton as a result, with many urging him to find a Plan B to get the best out of his team.
McCann is one of them and he names two players in particular who are looking lost in the current system.
“For me, there's something missing with Rangers at the moment,” he told the Daily Mail.
“Joe Garner was bought for £1.5million. He's said himself he wasn't used to this style of football. It's as if Joe's in the wrong movie.
“(Michael) O'Halloran is another one who looks like he's not enjoying the system. He looks like a guy who enjoys a 4-4-2, with a striker he can hit.”
If one stat highlights just how much Rangers need a plan B it is the number of times they have drawn games this season
Five of their 14 fixtures have ended in a draw; something that has cost them heavily in their attempts to keep up with Celtic.
It hints that the changes are needed to give Rangers that extra edge and it will be interesting to see if Warburton is willing to make them as the campaign progresses.