Wenger had come under pressure from fans to add to his ranks this summer, even before the sale of captain Cesc Fabregas to Barcelona earlier this week.
Walcott has now added his voice to the calls for new recuits following their opening day draw at Newcastle and a hard fought win over Udinese in their Champions League play-off, with injuries starting to stake up ahead of fixtures with Liverpool and Manchester United.
"This team has always been known for being young. But we can't use that as an excuse any more. We have to win something this season," he told a number of national newspapers, relating to the club's six-year trophy drought.
"It is important to have a mixture of experience and young players - but the boss knows what he is doing. He has picked up great players before. Only time will tell what he is going to do.
"Of course the players sometimes think, 'What's going on?' We've had a couple of injuries and we have to hope they are not too bad. We have got a fairly big squad but we don't want the squad to get lower and lower."