Newcastle invested more than £52million in their squad during the summer but have taken only two points from their opening six Premier League games.
It has been suggested Newcastle are still a central defender and a striker short, a problem exacerbated by the back injury which will keep frontman Papiss Cisse out of the cup game and a hamstring operation which will sidelines centre-half Steven Taylor for two months. The club have also been criticised for having the least number of English starters – one – in the Premier League.
“We have talked about spending in January,” McClaren said. “We have said this is about three windows.
“With the start, people will obviously criticise the first window, but the people we’ve signed are all good players. They need time to adapt to the Premier League.
“We know that January is coming up and it will be important. We talked as a club with Lee and Graham (Carr, chief scout), and said we are going to review the window in a couple of weeks, and the position in January.
“We’re reviewing everything and that (needing more British players) will be part of it.”
When asked if he had been left short of players, McClaren added: “I think every manager would, in hindsight, answer that by saying, ‘I wish we could have had him and him and him’. But we’ve had the time to do that and we’ve got what we’ve got. It’s time to get on with it.”
With the transfer window still some time away, McClaren has urged Newcastle’s fans to remain patient with the most recent set of signings.
“There has been a lot of criticism of the players coming in but it takes time,” McClaren added.
“The fans have been fantastic in terms of how they could have been. It’s a little bit of blind faith that is required, that belief that eventually we will get it right.
“It needs a lot of work but that is going on behind the scenes.
“I certainly believe that what we’ve got in there is good enough to turn it around and start winning.”