Ospina, who wants to leave Arsenal this summer amid interest from Turkish side Fenerbahce, suffered an injury during the Gunners 2-2 draw with Manchester City on Sunday and looked in considerable discomfort throughout the entirety of the second half.
The Colombia international didn’t take part in Arsenal’s pre-match training session at London Colney on Tuesday morning and his injury looks set to rule him out of the midweek match, with Argentine shot stopper Martinez set to replace him despite playing a mere three EFL Cup matches this campaign.
Petr Cech remains on the sidelines with a groin injury sustained against West Brom before the international break, meaning 22-year-old Matt Macey is likely to be named among the substitutes after being recalled from his loan spell with League 2 side Luton Town.
Meanwhile, Francis Coquelin isn't expected to be part of the squad for Wednesday’s game which could mean midfielder Mohamed Elneny starts in place of the Frenchman alongside Granit Xhaka, as Gabriel fills in for the injured Laurent Koscielny at centre-back.
Arsenal could close the gap on fourth placed Manchester City to four points with a win against Slaven Bilic's side but will be aware that Manchester United, who are in action against Everton on Tuesday, will be two points behind City if they record a victory.