Kelechi Iheanacho included in Nigeria's Olympics squad
Five England-based players have been named in Nigeria's 35-man provisional squad for the Olympic Games.
Midfielder John Mikel Obi, defender Kenneth Omeruo, strikers Odion Ighalo, Alex Iwobi and Kelechi Iheanacho are all with Premier League clubs.
Ighalo and Mikel are two of the three over-aged players allowed by Fifa, along with goalkeeper Daniel Akpeyi.
The squad includes 16 full internationals, but only eight players who are at Nigerian clubs.
"I feel honoured to be selected by my country and I hope to give my best at the Games if I make the final squad," Ighalo told BBC Sport.
But Iheanacho's participation in Brazil is in doubt after Nigeria coach Samson Siasia complained early this week that numerous letters from the Nigerian Football Federation to the striker's club, Manchester City, have gone unanswered.
The Olympic tournament, which is for Under-23 players, starts on 3 August, meaning Iheanacho would miss a big chunk of his club's pre-season preparations and summer tour of China.
If Nigeria progress from their group, Iheanacho would also be away for the start of the Premier League season. And if they reached the medal matches he would miss the first leg of the club's Champions League play-off.
Defender Omeruo, who spent last season on loan at Kasımpasa from Chelsea, is included in the provisional squad despite having earlier ruled himself out because of a groin problem.
Omeruo had revealed doctors told him he needed to rest over the close season but Siasia believes Nigeria have a strong medical team to look after the centre-back in Brazil.
Meanwhile, the NFF said the so-called 'Dream Team VI' would prepare for the Olympic Games in the United States and Mexico.
"The team will face the U-23 National Team of Mexico in Mexico on Saturday 2 July," the NFF said in a statement.
"The team will continue its training camp in the United States of America and will play Charleston Battery FC in Atlanta on Saturday 16 July. Another game against the Honduras U-23 team is also being planned for 27 July."
Nigeria, who have been drawn in Group B of the Rio Games alongside Sweden, Colombia and Japan, boast a proud Olympics record.
They made Olympic football history in 1996 by becoming the first African team to win the gold medal.
Nigeria also finished runners-up at the 2008 Beijing Olympics, where current Under-23 coach Siasia also led the 'Dream Team' in China.
Nigeria Provisional 35-man squad
Daniel Akpeyi (Chippa FC, South Africa), Yusuf Bala (Kano Pillars), Emmanuel Daniel (Enugu Rangers), Taiwo Abdulrahman (Kwara United), Ndubuisi Agu (FC Porto, Portugal), Junior Ajayi (CS Sfaxien, Tunisia), Stanley Amuzie (Olhanense FC, Portugal), Taiwo Awoniyi (Frankfurt FC, Germany), Okechukwu Azubuike (Yeni Malatyaspor, Turkey), Etor Daniel (Enyimba FC), Augustine Dimgba (Sunshine Stars), William Troost-Ekong (Haugesund FC, Norway), Saturday Erimuya (Kayseri Erciyespor, Turkey), Oghenekaro Etebo (CD Feirense FC, Portugal), Imoh Ezekiel (Anderlecht, Belgium), Saviour Godwin (Ostende, Belgium), Odion Ighalo (Watford FC, England), Kelechi Iheanacho (Manchester City, England), Alex Iwobi (Arsenal, England), Emiloju Julius (MFM FC), Kingsley Madu (AS Trencin, Slovakia), John Mikel Obi (Chelsea, England), Musa Muhammed (Istanbul Basaksehir, Turkey), Usman Muhammed (CF Uniao, Portugal), Wilfred Ndidi (KRC Genk, Belgium), Erhun Obanor (MFM FC), Godfrey Oboabona (Caykur Rizespor, Turkey), Kenneth Omeruo (Chelsea, England), Sodiq Saliu (Seraing FC, Belgium), Abdullahi Shehu (CF Uniao, Portugal), Moses Simon (KAA Gent, Belgium), Seth Sincere (Rhapsody FC), Ndifreke Udo (Abia Warriors), Aminu Umar (Osmalispor, Turkey), Sadiq Umar (AS Roma, Italy)