The news that Sergio Aguero has tested positive for Covid-19 has given Manchester City boss another selection headache, who might have seen the FA Cup tie at Cheltenham as an ideal opportunity to bring the striker back.
Aguero had been isolating having come into contact with a person who had tested positive for the virus, but was negative himself and might have been back for City's trip to the League Two minnows. On Thursday, however, he confirmed he has since tested positive and is isolating himself.
Guardiola was likely to make changes anyway, and the injuries to Kyle Walker and Kevin De Bruyne against Aston Villa probably won't have impacted his selection plans for the trip south on Saturday.
However, Guardiola does like to go strong in the cup, regardless of the opponent, and there may well have been a place on the bench reserved for Walker and De Bruyne. Now, he may have to call up more youngsters than previously planned so as not to risk his injured pair.
With the Under 23s side having taken six points from their two meetings with League Two opposition earlier in the season in the EFL Trophy, scoring seven goals and keeping two clean sheets, Guardiola could do worse than call up Taylor Harwood-Bellis and Luke Mbete to the squad in defence.
Aymeric Laporte could return after making his comeback from injury in training but not yet in the first team, while Eric Garcia might also be in line to start. Benjamin Mendy hasn't featured much in recent weeks, and was left on the bench when Walker went off against Villa as Aleks Zinchenko came on.
Harwood-Bellis and Garcia have both played at right-back in the past for the first team if Guardiola wanted to give Joao Cancelo a deserved rest, but if he wanted a more natural full-back he could do worse than call up Alpha Dionkou.
The right-back has impressed for the EDS against League One and Two opposition, and has been in first team training recently. He is an attacking option who likes to get forward and could also fit in a wing-back system.
Into midfield, where De Bruyne is likely to miss out, and Tommy Doyle would be deserving of another call-up, having relished his battles with professional opponents in the past. The holding midfielder fits seamlessly into Guardiola's system, and would benefit greatly from an experience like the one City will get at Cheltenham.
James McAtee and Ben Knight have also been impressive performers in the EFL Trophy and for the under-23s, so could be outside bets to make the bench. Jayden Braaf has also featured this season on the wing for the youths.
In attack, and Gabriel Jesus might be needed to start as he continues to be monitored on his return from having Covid-19. Liam Delap and Felix Nmecha would fancy their chances of making the matchday squad after getting a taste of first team football already this season. Delap scored a hat-trick but was also sent off in his last outing in the Premier League 2, but won't be suspended for the FA Cup.
Finally, Cole Palmer has been a familiar name on first team matchday teamsheets this season, and impressed on his senior debut at Burnley in the Carabao Cup. If Guardiola wants to rest any of his forward players with a busy schedule ahead, Palmer would be a solid option after his own good performances in the EFL Trophy and FA Youth Cup.