Wellens has missed the last two matches with a calf injury, but the midfielder is poised to come back into the reckoning at London Road.
“He trained this (Thursday) morning,” said Foxes boss Nigel Pearson. “Barring any reaction, he will be in the squad but it is really a case of seeing how players are on Friday now ahead of the game on Saturday.”
Andy King and Darius Vassell returned to action following injury as Leicester participated in a fundraising match for cash-strapped neighbours Kettering on Wednesday night.
Midfielder King, who was an unused substitute the previous evening as the Foxes drew 0-0 with Nottingham Forest, has been out since suffering a foot injury in January. Striker Vassell has been sidelined after undergoing knee surgery in October.
Pearson confirmed that King will be included in the squad again but said that Vassell would not feature.
Pedro stepped off the bench to send Chelsea into the FA Cup semi-finals after they beat Leicester 2-1 at the King Power Stadium on Sunday evening.
RB Leipzig came from behind at the Red Bull Arena to end a run of four winless games and defeat Bundesliga leaders Bayern Munich 2-1 on Sunday.