Poyet, right, has praised the impact Lampard, left, has had on Chelsea but believes the transfer window will be crucial for both him and the club

Former Chelsea midfielder Gus Poyet says the club must make a signing in the January transfer window to avoid “going backwards”, but warned the Blues must also be careful to not upset their promising youngsters.

Chelsea boss Frank Lampard was unable to sign any players in the summer due to a two-window transfer ban.

However, that was reduced on appeal, meaning players can now be signed.

“The transfer window will be very important,” said Poyet.

“Everything is all very good at the moment at the club but this is Chelsea. He is the manager of Chelsea and at this club you need to get to certain points and this transfer window could be key to that.

“You need to bring in a very special player but you cannot upset the atmosphere. You cannot take away one of the youngsters because otherwise you contradict yourself.

“At the same time you need something to help you get better because something is still missing there. There are some very important decisions to be made.”

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