Gnabry joined West Bromwich Albion on a season-long spell in August but was recalled after only making three appearances for the Baggies.
The Germany Under-21 midfielder had been sidelined for most of the 2014/15 campaign with a knee injury, and Wenger says that another loan move will be crucial for the 20-year-old’s development.
Serge's loan will be like what I did with Francis Coquelin last year and, if possible, I might call him back after.Arsène Wenger
“Serge will go to the Championship but we have to decide where today,” the manager said. “I know approximately but I wouldn’t like to make a wrong announcement.
“It’s between two clubs and I want to give him some competition because he didn’t play at West Brom. It will be like what I did with Francis Coquelin last year and, if possible, I might call him back after.”
Hector Bellerin’s fine form has restricted Debuchy’s playing time and Wenger believes it is also important for the France defender to gain more minutes.
“Debuchy [leaving] is also a possibility,” he said. “It will be a loan to a Premier League team because it’s impossible to conclude a permanent move now. At the moment it doesn’t look likely but it is still a possibility.
“I never thought we would do much more [transfer business] but I told you that we would do at least one transfer and if possible I would have been open to one more. But there is a rarity on the market of players and it is difficult to conclude anything at the moment.
“Whether we are 100 per cent [sure that nobody else will join] is difficult to say, but 99 per cent, yes. A miracle can always happen, though. Someone can knock on your door and if Messi knocks on my door 5.50pm tonight, I will not say, ‘Please go back to Barcelona!’”Copyright 2016 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source