The likes of Fikayo Tomori, Michy Batshuayi and Kenedy do not know if they will be staying at the club, going out on loan or permanently sold before the window closes.
According to Goal, Lampard has yet to make a final decision on these players.
He will assess them during pre-season before deciding whether they have a future at the club under his leadership.
Lampard is leading a youth revolution at Chelsea, driven in part by their FIFA transfer ban.
It gives the likes of Batshuayi and Kenedy a greater than expected chance to stake a claim for a first team spot.