Defending champions Mumbai Indians retained its core team, including veteran Sri Lankan pacer Lasith Malinga, despite his fitness issues, while releasing 12 players.
While releasing 12, the franchise, which has won record four IPL titles, retained 18 players which helped it win its fourth IPL title earlier this year.
They, however, released Australian fast bowler Jason Behrendorff and Alzarri Joseph of the West Indies, New Zealand's Adam Milne, Beuran Hendricks and Ben Cutting.
Former India all-rounder Yuvraj Singh, who quit all forms of cricket including the IPL earlier this year, was also released.
Kiwi seamer Trent Boult, West Indian Sherfane Rutherford and Mumbai pacer Dhawal Kulkarni are the three trade-ins for the franchise.
"Going into this December's auctions for the 2020 edition, Mumbai Indians now have the option of filling up slots for 5 domestic and 2 foreign players during the day-long event in Kolkata," read a statement from the franchise.
While Mumbai Indians traded out young leg-spinner Mayank Markande and batsman Siddhesh Lad to Delhi Capitals and Kolkata Knight Riders respectively, they additionally let go off six international and four Indian players.
Among those retained are skipper Rohit Sharma, all-rounders Hardik Pandya and his brother Krunal, spinner Rahul Chahar, wicketkeeper Ishan Kishan and pace spearhead Jasprit Bumrah.
South African wicketkeeper-batsman Quinton de Kock and Malinga were also retained.
Retained players: Rohit Sharma, Hardik Pandya, Jasprit Bumrah, Krunal Pandya, Ishan Kishan, Surya Kumar Yadav, Rahul Chahar, Anmolpreet Singh, Jayant Yadav, Aditya Tare, Anukul Roy, Dhawal Kulkarni (Traded in), Quinton de Kock, Kieron Pollard, Sherfane Rutherford (Traded in), Lasith Malinga, Mitchell McClenaghan, Trent Boult (Traded in).
Released players: Evin Lewis, Adam Milne, Jason Behrendorff, Beuran Hendricks, Ben Cutting, Yuvraj Singh, Mayank Markande (Traded out), Barinder Sran, Rasikh Salam, Pankaj Jaswal, Siddhesh Lad (Traded out), Alzarri Joseph.
