The 31-year-old, who came through the ranks at Upton Park, is back in London after moving from Liverpool on an 18-month deal.
"He didn't get the games at Liverpool," Wenger said.
"He's a player who reminds me how quickly time passes, because I saw him start his career when he came through the youth team at West Ham. Suddenly he's back there.
"At the end of your career, you certainly feel comfortable where you started. You feel loved and welcome at the moment when you need it and don't get as many games. That helps you a lot to find your confidence back."