Midfielder Mulumbu missed last weekend's 5-0 Championship rout of Watford after tweaking a knee ligament but was back in the fold on Tuesday to hand Di Matteo a selection poser, after Gonzalo Jara deputised well in the middle of the park alongside Graham Dorrans.
Roman Bednar was an unused substitute against the Hornets in what was his first game back since suffering a trapped nerve in his back, and he gained vital match practice for the reserves in midweek as they brushed aside Burton 10-0.
Northern Ireland international midfielder Chris Brunt also made his comeback from a calf problem and is again expected to start against the Foxes at the Walkers Stadium, despite being substituted just after the hour mark.
Simon Cox grabbed his first league goal for the club last weekend in what was only his second start and Di Matteo must now decide whether to keep faith will the former Swindon marksman, and indeed his entire starting XI, after seeing them get back to winning ways in style.
The Italian's only absentees remain long-term victims James Morrison (heel), Ishmael Miller and Neil Clement (both knee).