Yakubu and Darius Vassell are expected to return to boost Leicester's strike force for the visit of the Lions.
Yakubu was cup-tied as the Foxes lost to Manchester City on Tuesday night, while Vassell missed the third-round replay at Eastlands with a hamstring strain.
On-loan striker Yakubu is certain to come back into the reckoning but there is a slight doubt regarding Vassell's inclusion.
Should Vassell be deemed fully fit, fellow forward Martyn Waghorn is expected to join Championship rivals Derby on loan.
Boss Sven-Goran Eriksson is also hopeful that Paul Gallagher will recover from the knee injury that forced him off after 30 minutes against Manchester City.
Franck Moussa or Matt Oakley are options for Eriksson should Gallagher not make it.
Millwall have a host of injury worries ahead of the trip to Leicester.
Boss Kenny Jackett is without all four of his centre-halves as Paul Robinson, Danny Shittu (both hamstring), Tony Craig (back) and Darren Ward (ankle) are sidelined.
Midfielder Tamika Mkandawire, who played centre-back at previous club Leyton Orient, is also missing with a groin problem so manager Kenny Jackett has drafted in Danish defender Jens Berthel Askou on loan from Norwich.
The problems do not end at the back, either, with midfielder Liam Trotter a still a doubt with a back problem and striker Josh McQuoid missing with ankle ligament damage.
Theo Robinson could start in attack for the first time since completing his permanent switch from Huddersfield.