Nigeria are making their seventh appearance in the Olympics.
Sweden face Colombia in the men's football at the Estadio Nacional de Brasilia on Thursday.
Veteran goalkeeper Paul Jones has also arrived at Carrow Road on a free transfer.
Germany face Mexico in the men's football event on Thursday.
Argentina are two-time gold medal winners after triumphing back-to-back at Athens 2004 and Beijing 2008.
The USA begin quest to win fourth straight gold medal by beating New Zealand 2-0 in Belo Horizonte.
Iraq face Denmark in the men's football at the Estadio Nacional de Brasilia on Thursday.
The Gunners against completing deal for PFA Players' Player of the Year as rumours mount.
Honduras face Algeria in the Men's football at the Olympic Stadium on Thursday.
Oscar, Loic Remy, Asmir Begovic and Juan Cuadrado could all leave the Blues this summer.
Selecao begin quest to win Olympic gold medal on home soil with Group A clash against South Africa.
Mahrez scored 17 goals and provided 11 assists to help Leicester to the PL title in 2015/16.
The 30-year-old striker joined the Reds in 2004.
Paul Pogba left Manchester United on free transfer to join Juventus in 2012.
Walcott has struggled while playing as a central striker.
The 25-year-old attacker was among the best players in Europe last season.
Draxler joined Wolfsburg from Schalke last summer.
Barcelona star Neymar and the Selecao take centre stage against South Africa in Brasilia.
Portuguese keen to sign defender in the mould of former Red Devils captain Nemanja Vidic.
Kelechi Nwakali is the captain of the Nigeria U-20 team.
The 29-year-old joined Spurs in 2014, but failed to secure a first-team place.
The 17-year-old is considered to be an exciting prospect by the club.
Outspoken Swede joined Red Devils on a free transfer this summer.
The 19-year-old is considered to be among the best young players in the world
Defender's agent says it is 'normal' for his client to consider better offers.
Slaven Bilic claims Hammers "close" to securing latest signing after Aaron Cresswell injury.
Antonio Conte hints United States centre-back will leave the club this summer to gain experience.
Full-back joined Schalke on season-long loan after being told he was free to leave.
Former Spain international set to sign a two-year deal with an optional one-year extension.
Manager Garry Monk and owner Massimo Cellino pledge to retain 22-year-old defender.