Wales international Ramsey picked up a calf problem ahead of last week's pre-season friendly with Chelsea but made a welcome return to training on Thursday to boost hopes he will be passed fit for this weekend's clash at the Emirates Stadium.
However, it is looking increasingly likely that Monreal will miss the visit of the Premier League champions due to a knee injury, the left-back having only resumed light training on Friday.
In the absence of Monreal and with Sead Kolasinac ruled out for up to 10 weeks with a knee injury, Ainsley Maitland-Niles looks set to start at left-back against City.
Also missing from the Arsenal backline will be Laurent Koscielny (Achilles), while Danny Welbeck is unlikely to be risked after only returning to pre-season training at the start of the week following an extended break after the World Cup.
New coach Unai Emery will have to decide which of his five summer signings - Bernd Leno, Sokratis, Stephan Lichtsteiner, Matteo Guendouzi and Lucas Torreira - gets the chance to make their debuts in the Spaniard's first competitive game at the helm.