The 19-year-old didn't have a summer break, joining up with the Reds on their tour of the United States straight after featuring for England Under-19s in the U19 European Championships in Germany.
As a result, it's believed that the discomfort he complained of after returning from their pre-season tour comes from a regular workload which has caused him to fracture a bone.
Although minor, Ojo could be sidelined until at least mid-September with the issue - although reports suggest Liverpool are reluctant to name a timeframe for the forward's return.
That's because there is no specific recovery programme for Ojo, who simply requires a period of rest to allow the problem to subside and heal.
Ojo, who moved to Merseyside from MK Dons in November 2011, endured a strenuous 2015-16 season with his international commitments and the minutes he played in the US tour combined with a breakthrough campaign at Anfield.
He featured 11 times for Jürgen Klopp's first-team, after being recalled in January from a loan spell with Wolverhampton Wanderers in the Championship, where he scored three times in 17 appearances across all competitions.
That followed a temporary move to Wigan Athletic the previous year, also just a four-month loan, in which he played 11 times.
Ojo out for around a month with back problem
A few weeks ago, Ojo revealed that he rejected the opportunity to take a summer's holiday - choosing instead to join up with the Liverpool senior squad in the States.
But while he will have been hoping to impress Klopp, scoring in a 2-1 defeat to AS Roma, his time across the Atlantic appears to have had the opposite effect in leading to an injury lay-off.
The wide-man, who scored his first and only competitive goal for the club in the FA Cup back in January, will nonetheless hope to get straight back to business upon his return given that he is viewed as one of the club's brightest prospects.
His pace, power and direct running saw him make a splendid impact towards the back end of last season - breaking ahead of Jordon Ibe in the pecking order, with his compatriot sold to Bournemouth for £15 million in July.
In more positive news, Academy midfielder Pedro Chirivella is closing in on a return from a quad injury that caused him to miss a significant majority of the Reds' pre-season preparations.
He played in their first friendly at Tranmere Rovers on July 8 but was kept out from then. The Spaniard - likely to be a key member of Liverpool Under-23s squad in the Premier League 2 - has now been given permission to return to light training.
In addition to Ojo, only Joe Gomez (achilles), Mamadou Sakho (achilles), Loris Karius (broken hand) and Lucas Leiva (hamstring) remain out of Liverpool's formerly seven-strong injury list - with Daniel Sturridge and James Milner having returned to training.