The Cottagers face the Polish champions without some key players, including Danny Murphy, Clint Dempsey and Bobby Zamora.
The latter pair have been rested ahead of Sunday's Premier League match against Everton, while skipper Murphy misses out with a knee injury.
Despite the big-name absentees, Jol remains confident of victory at the Stadion Miejski and backed his squad players to rise to the occasion.
"Danny took a knock to his knee, which was pretty painful but hopefully he will be fit for selection on Sunday," the Dutchman said.
"I spoke to the medical staff and we decided not to take a risk.
"Dempsey was left in London and Bobby was the same as I want him for Sunday rather than risking him tomorrow because we have got Andrew Johnson.
"[Mousa] Dembele is with us even though he had a little problem with his ankle and we have Orlando Sa, who can also play in attack.
"We took a few younger players instead [rather than risking them] like Kerim Frei, Alex Smith and Marcel Gecov.
"That said, I do not have any concerns before the match.
"We have played with different teams before and have 22 good players, as well as a few younger players.
"Overall, we still have a very strong team."
Fulham remain undefeated in Group K but progression for Wisla already looks unlikely, having lost their opening two matches and conceded seven goals in the process.
The poor performances means little more than 15,000 are expected at Thursday's match - less than half the capacity of the Stadion Miejski.
Wisla's defeats have seen fans and pundits alike turn on a supposedly slow and disorganised defence, which Jol believes makes this the kind of game in which a player of Johnson's pace could flourish.
"If he starts I think he can do well," he said. "He has scored I think six goals in Europe and then against QPR, where he scored a hat-trick.
"He is on fire and I think the only decision we have to make is whether we play him or somebody else."
Johnson started Saturday's Premier League clash at Stoke, where late goals from Jon Walters and Rory Delap condemned Fulham to a 2-0 defeat.
"Stoke was of course very disappointing because we were doing okay for 80 minutes and then their strength showed," Jol said.
"We were pretty disappointed after that but I don't think it has anything to do with this game.
"This game is important in another way, another perspective and we want to do well in the group. We want to do well in Europe.
"You cannot compare the two competitions but it is always good to have a win under your belt so I would say it is important for the confidence."
Fulham midfielder Dickson Etuhu echoed his manager's sentiments, adding: "Obviously we are expecting a tough game tomorrow.
"Every time you play in Europe, especially away from home, you expect a difficult game.
"I've heard a lot about this club and how tough it is to play at their ground, how amazing the atmosphere is.
"We're looking forward to it and it is an experience for all of us."