The Real Sociedad star sustained the injury during a friendly match against Guinea, marking another setback for the Super Eagles squad already grappling with several injury concerns.
The blow comes at a critical juncture as Nigeria gears up for their opening AFCON clash, and the absence of the talented strikers will undoubtedly impact the team's dynamics on the competition.
The Super Eagles player has missed the team's last two training sessions, and the prognosis suggests that he is unlikely to regain fitness in time for the crucial match.
During Wednesday's training session at the Ecole Nationale de la Police, Sadiq trained separately from his teammates, indicating the severity of the injury.
The disappointment was palpable as the young striker, known for his prowess on the field, sat out the training at the same venue on Thursday night.
With 22 players actively participating under the watchful eye of head coach Jose Peseiro, the absence of a key players like Real Sociedad's forward cast a shadow over the team's AFCON campaign.
Super Eagles' striking woes: Boniface out, Iheanacho doubtful, Osimhen lone striker
The injury concerns for the Super Eagles do not end with Sadiq Umar.
The absence of key players like Ndidi and the doubtful status of Iheanacho have further added to the team's woes.
Bundesliga striker Victor Boniface has already been ruled out of the competition, leaving Napoli forward Victor Osimhen as the lone fit striker available for the upcoming game against Equatorial Guinea.
In a race against time, Kelechi Iheanacho, who has recently recovered from a muscular problem, is expected to join the Super Eagles squad on Saturday.
However, uncertainties loom over his readiness for the match.
The absence of key players and the last-minute nature of Iheanacho's potential inclusion pose significant challenges for the coaching staff in terms of strategy and player selection.
Super Eagles call up Paul Onuachu as replacement for injured Sadiq Umar at AFCON
OGC Nice's player from France, a replacement for the injured Terem Moffi, is anticipated to join the team on Sunday.
The Super Eagles have extended a late call-up to Paul Onuachu to fill the void left by Sadiq Umar's unfortunate injury.
The dynamics of the team will undergo adjustments as the coaching staff navigates through the challenges posed by these unexpected setbacks.
As the Super Eagles regroup and strategize for the AFCON clash, the resilience and adaptability of the team will be put to the test.
The tournament's unpredictable nature, coupled with the uncertainties surrounding player availability, adds an extra layer of complexity to Nigeria's quest for glory in the prestigious competition.
The footballing world watches with bated breath as the Super Eagles face the uphill task of overcoming these hurdles and making their mark in AFCON history.
This article was most recently revised and updated 1 month ago