"We showed that we are able to get players in, even when they are not on the market because if players are on the market it is different," said Jol.
"If you were president, chairman or chief executive at another club you never try and get rid of your best players - so we have to try and be inventive.
"We have to try to get the players who are not playing well or not fitting in at their other clubs, but they have to be better than the players we have got so we will come up with one or two solutions.
"We are looking for good players and they are always under contracts with other clubs, you have to pay but if they are playing well, we wouldn't sell [Dimitar] Berbatov now, it means other clubs won't do that.
"It is not an easy situation but we know maybe one or two players who are having problems at their clubs - we always look to strengthen and if it possible we will do it."