"I've got 20 players following all the injuries and we're a little short," Coppell told the club's website after watching City lose 2-1 at Torquay.
"As always I think there will be an avalanche of business done in the final week ahead of the new season."
He added: "There are an awful lot of phone calls going on at the moment but not a great deal of substance to those calls."
Last season's top scorer Nicky Maynard and fellow-striker Danny Haynes are still sidelined, while at the back, captain Louis Carey, Christian Ribeiro and James Wilson have yet to feature in any pre-season games.
Coppell said: "You can't wait, you have to try and do something about it."
David Clarkson gave City the lead ten minutes after the break at Torquay but second-half goals from Lee Mansell and Mark Ellis sealed victory for the Devon side.
Source: BBC Sport
Source: BBC Sport