The 26-year-old has been missing for seven months due to a knee injury but now he has rejoined the training again. He left the pitch in May with an injury he suffered during a match against Manchester City.
Wenger is happy about the news and said: "t is fantastic. For him, it is like starting a new career because he has been out for such a long time".
He netted 13 times in 49 appearances since he joined them in 2014 from United.