The decision facing the IOC in May/September 2013

8th September 2013: The sport of Wrestling was elected by the IOC as an additional sport for the Summer Olympic Games of 2020 and 2024. The decision was made at the 125th Session of the International Olympic Committee (IOC) in Buenos Aires, Argentina.

Voting was:-
Wrestling: 49
Baseball/ softball: 24
Squash: 22

29th May 2013:

Eight sports including Wrestling presented to the IOC Executive Board in St Petersburg, Russia, explaining why they believe that they should join the 25 core sports + Golf + Rugby Sevens in the 2020 Olympics.

Wrestling, Squash and Baseball-Softball were successful and were invited to present to the 125th IOC Session, Buenos Aries, on 8th September 2013

Sport
Wrestling
Baseball-Softball
Squash
Karate
Rollersports
Sports climbing
Wakeboarding
Wushu (martial arts)

12th February 2013:

Decision by the IOC Executive Board to reduce the number of core sports to 25

Prior to the Executive Board, The IOC Programme Commission considered Questionnaire returns by the International Federations agains 39 criteria. (Link to Criteria)

The 25 Core Sports

Archery
Athletics
Badminton
Basketball
Boxing
Canoeing
Cycling
Equestrian
Fencing
Gymnastics
Handball
Hockey
Judo
Modern Pentathlon
Rowing
Sailing
Shooting
Soccer
Swimming
Table tennis
Taekwondo
Tennis
Triathlon
Volleyball
Weightlifting