The Cottagers look set for another mid-table finish after dealing with the loss of Clint Dempsey and Mousa Dembele at the start of the campaign thanks to the introduction of a number of loan signings.
But the likes of Sascha Riether, Urby Emanuelson, Eyong Enoh, Emmanuel Frimpong and Eyong Enoh see their loans end soon, while several key players are also out of contract.
Jol feels that is a worry and is keen to tie more players down to longer-term deals in the future.
"We've got to rebuild again and the concern is that we have to keep doing that each season," said the Dutchman. "If you have £25million to spend on a 23-year-old, that is what we would like to do.
"But if you saw the last transfer window a lot of players went on the final day and you can't make these £10-15m offers to other clubs then.
"Last year I though there were one or two pieces of the jigsaw left to fill in - and then Dembele and Dempsey left.
"I couldn't put my money where my mouth was so that was a bit frustrating, but on the other hand this is not a Mickey Mouse league and we have to survive and maintain where we are.
"We've had to be creative and that is good in the short term but in the longer term it isn't what you want.
"I know a lot of players who could do well, but structurally for the long term it is not ideal, so I would love to decrease the amount of loan players in the future."