Arsenal duo Olivier Giroud and Nacho Monreal ruled out until mid-January

Arsene Wenger has confirmed Olivier Giroud and Nacho Monreal have been ruled out for the foreseeable future due to injuries.

Arsenal make the short trip to Selhurst Park on Thursday night to take on Crystal Palace, but will have to do without two key players.

Giroud is set to miss at least three weeks to a hamstring issue and will not return until the middle of January at the earliest.

It means the French striker will be definitely sidelined for Chelsea’s visit to the Emirates.

Arsenal play Chelsea three times between January 3 and January 24 and Giroud could miss all three of those London derbies.

Monreal limped off against Liverpool last weekend and Wenger has confirmed the full-back is expected to be out until mid-January.

The injury at the back could mean a formation reshuffle from Wenger who has been deploying a three-man defence with Monreal one of the centre-backs.

Arsenal have found new solidity with a three-man defence, but the injury to Monreal could force a change.

Monreal has been ruled out of the next three games against Crystal Palace, West Brom and Chelsea, but could be fit for the EFL Cup clash with the Blues on January 10.

Giroud’s return date is far less positive with Wenger believing January 20 is the earliest the frontman could resume action.

The injury to Giroud increases the pressure on Alexandre Lacazette, with Arsenal’s busy festive period well underway.

Danny Welbeck and Theo Walcott could be restored to the starting line-up in a bid to decrease Lacazette’s workload.