The 18-year-old played for Holloway whilst on loan with Plymouth last season, but has since returned to Chelsea.
Sinclair has fallen down the pecking order at Stamford Bridge with the return to fitness of Florent Malouda.
Leicester boss Hollway told BBC Radio Sheffield: "Someone like Scott who I have borrowed before would be a great option"
"We have asked about him, and we're waiting on a reply".