Kayal is almost certain to miss the game after damaging his groin.
He lasted only 22 minutes of the 2-2 draw with at Celtic Park. Van Dijk felt a twinge in his hamstring, but could still feature against Karagandy, who bring a 2-0 lead to Glasgow following last Tuesday's first leg.
There were already injury fears surrounding Georgios Samaras and Kris Commons but the Celtic manager is confident both will be fit enough to return to the starting line-up.
"They are looking really optimistic," Lennon said. "James Forrest and Derk Boerrigter are probably 50/50.
"We will have to see how they come on in the next couple of days. Anthony Stokes had a scan and it is a Grade One calf strain. He is doubtful.
"Kayal will be out. Virgil got a wee bit of twinge as well from his hamstring.
"So we are really, really stretched, but it is what is and you have got to get on with it.
"Stokesie did a little light training on Thursday and he felt it again. The scan has proved there is more than just a kick there.
"He thinks he might be able to participate but we will have to see how it is."
Lennon denied that Celtic have made an offer for Cameron Stewart, the Hull City winger, but reiterated his hope of signing two players early this week, one a striker and one a midfielder.
"We are looking to get one done over the next couple of days," Lennon said. "We have another one's representatives in on Monday, so I am hoping we will have two by midweek."