Claudio Ranieri says his new signings will need time to adapt to the demands of the Premier League, as he defended his side's recruitment policy.
The reigning Premier League champions champions are struggling at the wrong end of the league standings, with just three wins from 13 games, having heavily strengthened their side in the off-season.
The Foxes brought in Nampalys Mendy from Nice for £13m, Ahmed Musa from CSKA Moscow for £16.6m, Islam Slimani from Sporting Lisbon for £30m, Bartosz Kapustka from KS Cracovia for £5m, and Ron-Robert Zieler, for an undisclosed amount.
While Slimani has scored five goals in 10 games, Musa has struggled to make an impact, and Mendy, who was expected to fill the void left by the departure of N'golo Kante to Chelsea, has been out injured with an ankle injury since August.
Kapustka is yet to start, while Zieler has been an able deputy to Kasper Schmeichel.
And ahead of his side's trip to Sunderland this Saturday, Ranieri said: "The recruitment is very good and I'm very happy but of course it's not always certain when you bring new players that they start very well.
"If you saw Riyad [Mahrez], he started [playing well] in the second year, the first year was normal. If he needed six or seven months then imagine the others.
"But the recruitment and the system of the recruitment I'm happy with."
Reports suggest the Foxes are looking to sign 19-year-old Genk midfielder Wifred Ndidi in January, while Ranieri confirmed the club were also targeting an extra defender.
He added: "Yes of course, for this reason we are looking in all directions and we need somebody."