While the speculations regarding the addition of the sixth team came ahead of 2017 edition of the tournament, franchise owners were reluctant to add another side in the competition.
However, the PSL supremo has now confirmed that next year's tournament would feature six teams, with the number of matches also increasing from 24 to 34.
Najam further insisted that he would also try to bring at least eight matches in Pakistan unlike the second edition in which only final was staged in Lahore.
"Next year: six teams, 34 matches, will try for up to 8 matches in Pak! Inshallah!," Najam wrote on Twitter.
Peshawar Zalmi won the PSL title in 2017 after thrashing Quetta Gladiators by 58 runs in front of a jam-packed Gaddafi Stadium in Lahore.
Next year: six teams, 34 matches, will try for up to 8 matches in Pak! Inshallah! https:t.co/FaL81RiNKD- Najam Sethi (@najamsethi) April 7, 2017