Vardy, who turned 31 on Thursday, has recovered from the groin injury that kept the England global out of the 2016 champions line-up for the FA Cup third round 0-0 draw with his former club Fleetwood Town last weekend.
Chelsea are expected to field a full-strength side against Leicester. Captain Gary Cahill was rested for the midweek Carabao Cup semi-final first-leg with Arsenal and could return in defence.
That being said, Toffees manager Sam Allardyce indicated prior to Barkley's move he could be fit in "early January", meaning a week in Chelsea training could be sufficient for the player to feature in some aspect.
Nigeria boss Gernot Rohr said earlier this week he expected Iheanacho and global team-mate Ahmed Musa to leave the King Power Stadium due to their lack of action but Puel dismissed any exit talk.
Meanwhile, Danny Simpson faces a late fitness test on his hamstring.
The west London side's last Premier League game saw Antonio Conte's men squander a lead to draw 2-2 with Arsenal at the Emirates Stadium following Hector Bellerin's late equaliser. They play at home. Jose Mourinho and Carlo Ancelotti also won 25, with Mourinho drawing and Ancelotti losing their 31st home games in charge.
Since August 2014, Vardy has scored more Premier League goals against "big six" opposition than any other player (22 goals in 41 apps).
He was asked to protect the back four so he wouldn't be able to get forward as much as he did when he played domestic games. They struggled in what was a poor game.
"I think it is a good thing to have some players like that with speculation in the transfer window", said Puel.