Genk have not put an exact timeframe on his return but Onuachu has been ruled out for up to four weeks, with the Nations Cup set to kick off in 20 days' time.

"He suffered a muscle tear. I already had the feeling that I had to replace him, but he said he could continue." Genk manager Bernd Storck told Belgian newspaper Sporza.

"And then he suffered a hamstring injury during a spurt. He will not be able to play for the next three, four weeks."

His injury is another blow to Nigeria ahead of the tournament, which begins on 9 January, as the Super Eagles sweat over the availability of Napoli's Victor Osimhen and Watford midfielder Oghenekaro Peter Etebo.

Onuachu, who has scored 12 league goals so far this season, was almost certainly going to be on the provisional squad list of interim Nigeria coach Austin Eguavoen.

His injury could mean that in-form Union Berlin striker Taiwo Awoniyi and Emmanuel Dennis of Watford are named in the preliminary squad.

Nigeria start their Nations Cup Group D campaign against seven-time champions Egypt on 11 January in Garoua before facing Sudan four days later and Guinea-Bissau on 19 January.

Onuachu, who was the top African scorer in Europe last season with 33 goals, was expected to play a prominent role for the three-time African champions in Cameroon.

In March 2019, Onuachu scored Nigeria's fastest-ever international goal against Egypt on his full debut, which helped the Super Eagles to their first victory over the Pharaohs in 29 years.

He then had to wait two years for his second goal, and this time he scrambled in Nigeria's winner deep into injury time as they beat Benin 1-0 in Porto Novo in March to celebrate qualification to the 2021 Nations Cup.

Three days later, he scored his third goal international goal in 10 appearances and helped Nigeria coast to a 3-0 win over Lesotho as they wrapped up their qualifying campaign unbeaten, finishing top of Group L.