Smith and De Villiers will feature in the tournament for the first time.
Out-of-form Umar Akmal was relegated to gold from platinum category.
Last time around, he was included in the Platinum category.
Will the foreign players agree to play in Pakistan?
De Villiers had yesterday announced that he will be playing the PSL.
The cricket board is also yet to zero in on the title sponsorship.
Earlier today, he confirmed that he will be playing in the PSL.
He will also play in the IPL for RCB.
In the interim, there are ongoing talks with the Australian duo of David Warner and Steven Smith.
The former speedster is currently involved with the Lahore Qalandar franchise of the Pakistan Super League.