Diaby is one of several players likely to be drafted in by Arsene Wenger, who is expected to rest the majority of his first-team players ahead of Saturday’s Premier League derby against Tottenham, with youngsters Hector Bellerin, Isaac Hayden, Chuba Akpom and Semi Ajayi all likely to be given a chance.
The 28-year-old Diaby has been plagued by injury setbacks since joining Arsenal eight seasons ago, suffering a broken ankle in a tackle from Sunderland defender Dan Smith in May 2006 and most recently undergoing surgery following anterior cruciate ligament damage in his left knee which sidelined him for all but the final match of last season.
Wenger, though, believes the France international, who played 90 minutes for the Under-21s last week, is still able to be competitive at the highest level.
“He is a giant, mentally,” said the Arsenal manager. “To do what he has done, with the severe injuries he had, he comes back every time, is dedicated and he deserves a lot of respect.
“I am a huge believer in his quality and I am sad as well that he couldn’t show it more. If there is some justice, the future will be much better for him.”
Francis Coquelin, Tomas Rosicky, Joel Campbell and Lukas Podolski are all fighting for starting roles at the Emirates with Colombia goalkeeper David Ospina, signed from Nice in the summer, expected to make his debut.
“We still have a team of experienced players, and we want to do well in this competition,” said Wenger.
“I believe this is an opportunity to give a game to players who need it and we go into a period where we play, and play, and play, and we want to continue to win our games.”
Southampton graduates Alex Oxlade-Chamberlain and Calum Chambers could feature against their former club and Wenger says he has been impressed by new manager Ronald Koeman, who took over a difficult job in the summer following the departure of Mauricio Pochettino to Tottenham as well as the sale of several key men.
“They are miracle workers at Southampton and you must say everybody expected them to collapse,” said Wenger. “They lost the spine of their team, they lost their manager and they bounced back in a such a way.
“I must say when I saw them against Liverpool where they lost the game, I thought straight away that this team is very strong and very good.”
Koeman fielded a strong side in the previous round of the Capital One Cup – a 2-0 win at Millwall – and the Dutchman plans to do the same again at the Emirates Stadium.
Senegal forward Sadio Mane could make a belated debut having finally been granted a work permit more than three weeks after completing a £10million move from Red Bull Salzburg on transfer deadline day.
James Ward-Prowse and Maya Yoshida should be available despite picking up ankle injuries against Swansea last weekend but Belgium defender Toby Alderweireld is again likely to miss out through hamstring trouble.
“It’s a difficult match but like I said before, in the League Cup against Millwall, we like to win everything,” said Koeman.
“If a player’s in good shape he’s able to play. We don’t take risks, but normally we like to play our strongest squad for Tuesday.”
Midfielder Morgan Schneiderlin insists the club can back up their impressive start to the campaign by winning silverware.
“Why can’t Southampton win a cup this season? Anything is possible,” he said. “We’re going to go to Arsenal, play our game and do the best we can.
“The players at this club want to do something great in the cup, it’s very important to us. It’s the shortest way to get into the Europa League, which would be great for the club and for the fans.”