Saturday's 1-0 defeat by Everton at Goodison Park was a third in succession for Jol's men, and they have claimed just one point from their last five fixtures.
But with 40 points already on the board and only one place in the drop zone left to be filled following QPR and Reading's relegation on Sunday, Jol is already looking to next season.
The Dutchman told reporters: "We will always find players like Mladen Petric or Hugo Rodallega.
"But, of course, it's not easy. I think we had five new players in, so it's not easy to settle.
"I'm satisfied we've got the points to be safe, although I'm a bit disappointed we couldn't get more points in the last few weeks and gone even higher."