The trio of striker Liam Delap, along with midfielders Roméo Lavia and Tommy Doyle didn't feature in the Sky Blues' 2-0 win against Preston - which marked the start of their pre-season on Tuesday.
Several academy stars featured in the win after returning to training following the COVID-19 outbreak at the club's training ground, which forced members of the academy bubble to self-isolate.
Though plenty of first-team stars are due to return from their respective breaks following their involvement in the European Championships and Copa America, Pep Guardiola could call upon a number of senior players against Barnsley on Saturday.
As per Stuart Brennan of Manchester Evening News, striker Liam Delap is still recovering from injury, and is set to sit out his side's second game of pre-season, whilst Romeo Lavia is struggling for fitness but could be involved against the Championship side.
Tommy Doyle has returned to training and could feature too, while first-team players such as İlkay Gündoğan, Oleksandr Zinchenko and João Cancelo could also be given a run out, having returned to training this week.
The Tykes were originally scheduled to play Watford on Saturday, but Manchester City successfully hijacked the clash, and will now face off against the impressive Championship outfit.
Pep Guardiola's squad were due to travel to France to face fellow City Football Group side ES Troyes AC on July 31st, but due to changes in UK quarantine rules for travellers returning from France, the match was called off earlier this month.
The cancellation of the fixture added to the cluster of problems facing Manchester City's preparations ahead of the defence of their Premier League crown.
The Sky Blues will now face off against Barnsley before their Community Shield clash against Leicester on August 7th, with one eye solely focused on their opening weekend Premier League clash at Tottenham the following week.
You can follow us for live updates here: @City_Xtra