Transfer window signing Gabriel could make his debut in defence when FA Cup holders Arsenal play Middlesbrough in Sunday's quarter-final at the Emirates Stadium.
Gabriel: Could debut for Arsenal on Sunday
Midfielder Aaron Ramsey (hamstring) is out for around two weeks, while forward Alexis Sanchez may not be risked after taking a blow to the knee in the midweek defeat of Leicester.
England international Jack Wilshere could return following a lengthy absence after ankle surgery, but Alex Oxlade-Chamberlain (groin) Mikel Arterta (ankle), Abou Diaby (calf) and Mathieu Debuchy (shoulder) are all still out.
Middlesbrough are missing Dani Ayala for the cup clash with Arsenal, with boss Aitor Karanka revealing the defender could be out for "three or four weeks" following the injury he picked up against Blackpool.
Adam Forshaw is also absent due to being cup-tied, while Tomas Kalas will not feature due to the nature of his loan deal.
George Friend is expected to be fit, along with Ryan Fredericks and Emilio Nsue, who is back from his Africa Cup of Nations exploits with Equatorial Guinea.