The Napoli forward could not make the trip from Abidjan to Bouaké with the rest of the Super Eagles team on Monday night.
A statement by the Super Eagles' official X (formerly Twitter) account reads: “Members of the team travelled from Abidjan to Bouaké today via a 10pm Air Cote D'Ivoire flight. Osimhen did not, however, make the trip as a result of an abdominal discomfort.
“Team medics confirmed that he has been placed under close watch with a member of the medical team staying behind in Abidjan with him.
“If cleared by tomorrow morning, he will join the rest of the squad before 5pm.”
It's important to note that Osimhen was stretchered off in the dying minutes of Nigeria's quarter-final clash with Angola.
Although the 25-year-old was treated on the sidelines and came back on the pitch for a few minutes, he didn't get to complete the game.
While it seems Osimhen isn't battling any major injuries, he'll face a late fitness test ahead of Nigeria's AFCON 2024 semi-final clash with Bafana Bafana.
Potential Osimhen replacements for Nigeria vs South Africa
In the scenario where Osimhen isn't fit for action, Nigeria's coach José Peseiro will have to call upon another player to take his place in the Super Eagles starting XI vs South Africa.
These are potential replacements for Osimhen:
Kelechi Iheanacho picked up an injury shortly before the start of AFCON 2024. In spite of his injury, the Leicester City player joined the team for their Nations Cup campaign.
As it stands, Iheanacho is yet to participate at this tournament, and Super Eagles fans haven't received a positive update on his injury.
The 27-year-old tends to perform well for Nigeria, as he was directly involved in at least one goal in his last five appearances for the Super Eagles.
If Iheanacho is fit to play, he should be Peseiro's first choice to replace Osimhen.
Ahmed Musa was a part of Nigeria's AFCON 2013 winning squad, and interestingly, he scored in the semi-final against Mali 11 years ago.
The Sivasspor player also started six of Nigeria's seven games when they won bronze at AFCON 2019. As a matter of fact, he captained the Super Eagles in five of those matches, including their 2-1 victory over Bafana Bafana in the quarter-final.
Although Musa hasn't scored for Nigeria since November 2021, he provided two assists in their victory over Sao Tome in the qualifying rounds of this tournament.
Like Iheanacho and Musa, Terem Moffi is yet to play in AFCON 2024.
The 24-year-old has been in sensational form for Nice this season, scoring six goals and providing two assists in France's top flight.
Moffi has scored four times in 14 appearances for the Super Eagles since his debut in June 2021. He scored twice in Nigeria's 10-0 victory over Sao Tome & Principe in the qualifying rounds of AFCON 2024.
Unlike Iheanacho and Musa, Moffi has never played a Nations Cup match.