The England winger's performances are thought to have suffered after he missed the Christmas fixture against Wolverhampton Wanderers through illness.
However, Wenger hopes that a return to his best will see the 22-year-old sign a new deal at the Emirates Stadium.
"I think he is coming back now," he told the club's official website. "He had a dip over Christmas.
"I found people were a bit harsh on him at Swansea because in the first half he looked dangerous to me. In the second half he scored the goal and having seen the game again he created some dangerous situations.
"The expectation level in England is very high for him because he started at the age of 16. But I still feel he has improved a lot this season. I am confident [that he will sign a new deal] yes, but let's see."
The Gunners host Manchester United in the Premier League tomorrow (Sunday).