Arsenal summer signing Lucas Perez is set to be out of action until December after damaging the ligaments of his left ankle during the 2-0 EFL Cup fourth-round victory over Reading, IBTimes UK sources understand. The news is a big blow for Arsene Wenger ahead of a busy November which will see the Gunners face key games against Tottenham Hotspur, Manchester United and Paris Saint Germain.

The 28-year-old number nine was selected ahead of Olivier Giroud to start against Reading after he netted a brace in the third-round victory over Nottingham Forest. However, the former Deportivo la Coruna star was forced off in the 72nd minute when Danzell Gravenberch caught his left ankle with a heavy tackle just moments after coming off the bench.

The Spaniard tried to continue but had to be replaced by Chris Willock minutes later. Subsequent medical tests have confirmed the worst as IBTimes UK understands he has damaged the ligament of his ankle and could be out of action for around six weeks.

Lucas is ruled out for the Premier League clash at Sunderland this weekend (29 October), and the whole of a busy November that sees them play Ludogorets, Tottenham, United, PSG, Bournemouth and the EFL Cup quarter-final against Southampton.

He is expected to return in December and be ready for the Christmas period. But the news is a big blow to the striker's hopes – already hit by Giroud's return from injury – of establishing himself in Wenger's starting 11, following his £17m arrival from Deportivo. The Spaniard was starting to become a regular in Wenger's plans, having played a part in the last three games against Reading, Middlesbrough and the 6-0 win against Ludogorets, providing two assists for Mesut Ozil after coming off the bench.