The Brazilian has joined Gremio on-loan.
"He moved because he'd lost a bit of confidence and he needs to play," Wenger said. "He's a guy who's a very good football player, but he didn't get enough games.
"He's more at ease in my opinion on the left of midfield, where there's a lot of competition. He will be back at the end of July, and of course he can have a future at Arsenal. That depends as well on the ins and outs during the summer."